33rd International Workshop on Deep Inelastic Scattering and Related Subjects (DIS2026)

4 May 2026, 08:00 → 8 May 2026, 18:00 Europe/Rome

Hotel Carlton

Francesca Bellini (Istituto Nazionale di Fisica Nucleare), Pietro Antonioli (Istituto Nazionale di Fisica Nucleare), Roberto Preghenella (Istituto Nazionale di Fisica Nucleare)

Overview

The 33^rd International Workshop on Deep Inelastic Scattering and Related Subjects (DIS2026) will be held in Bologna, Italy, from May 4 to May 8, 2026.

DIS2026 is the 33^rd in an annual series of International Workshops covering a broad mixture of material related to Quantum Chromodynamics and Deep Inelastic Scattering as well as a general survey of the hottest topics in high energy physics. A significant part of the program is devoted to the most recent theoretical advances and results from large experiments at BNL, CERN, DESY, FNAL, JLab and KEK. 

The venue of the workshop is the Royal Hotel Carlton Conference Centre, located in Bologna city centre and will be in person only.

The conference fee includes coffee/tea, lunches and social dinner on Wednesday evening.

The Workshop is co-organized by the INFN Divisions of Bologna and Ferrara, the Department of Physics and Astronomy of the University of Bologna, and the Department of Physics and Earth Sciences of the University of Ferrara.

Call for abstracts and early registration are open since 24th November 2025. Abstract submission deadline is 25th January 2026. All the important dates are visible on the main site.

 

 

Scientific Program

The DIS2026 workshop hosts a number of plenary sessions (Monday and Friday) and parallel sessions (Tuesday to Thursday).

The invited plenary speakers and topics are listed here: https://dis2026.infn.it/invited-plenary-speakers/

The parallel sessions are organized in 6 working groups. The WG conveners are listed here:
https://dis2026.infn.it/working-group-conveners/

WG1	Structure Functions and Parton Densities
WG2	Small-x, Diffraction and Vector Mesons
WG3	Electroweak Physics and Beyond the Standard Model
WG4	QCD with Heavy Flavors and Hadronic Final States
WG5	Spin and 3D Structure
WG6	Current Upgrades and Future Experiments

DIS2026-GroupPhoto

excursion.pdf

First Bulletin

Hotel Carlton DIS2026 map

Poster

Privacy-Notice-DIS2026.pdf

Second Bulletin

social_dinner.pdf

Template and instructions for proceedings package

Third Bulletin

Monday 4 May

08:00 → 09:30 Registration

09:30 → 10:00 Opening session

09:30 Welcome from Workshop Organisers

Speaker: Pietro Antonioli (Istituto Nazionale di Fisica Nucleare)

Welcome.pdf

09:35 Welcome from director of INFN - sezione di Bologna

Speaker: Eugenio Scapparone (Istituto Nazionale di Fisica Nucleare)

09:40 Welcome from deputy director of Department of Physics and Astronomy, University of Bologna

Speaker: Elisa Ercolessi (Istituto Nazionale di Fisica Nucleare)

09:45 Information about the workshop

Speakers: Francesca Bellini (Istituto Nazionale di Fisica Nucleare), Roberto Preghenella (Istituto Nazionale di Fisica Nucleare)

[DIS2026] Information.pdf

10:00 → 11:00 Plenary 1

Convener: Amanda Cooper-Sarkar

10:00 Global analyses of PDF

Speaker: Dr Juan Manuel Cruz Martinez (Universidad de Sevilla)

juan_cm.pdf

10:30 Lattice QCD

Speaker: Constantia Alexandrou (University of Cyprus & Cyprus Institute)

CA-DIS.pdf

11:00 → 11:30 Coffee break

11:30 → 13:30 Plenary 2

Convener: Robert Thorne (University College London)

11:30 High-pT physics and jet production

Speaker: Dr Francesco Giuli (Istituto Nazionale di Fisica Nucleare)

FGiuli_Plenary_DIS26.pdf

12:00 QCD simulations and Monte Carlo

Speaker: René Poncelet (IFJ PAN Krakow)

2026.05.04-Bologna-DIS26-poncelet.pdf

12:30 Precision QCD

Speaker: Tiziano Peraro (Istituto Nazionale di Fisica Nucleare)

dis2026TP.pdf

13:00 Highlights and prospects on electroweak, Higgs and top physics

Speaker: Beatriz Ribeiro Lopes

DIS2026.pdf

13:30 → 15:00 Lunch break

15:00 → 16:30 Plenary 3

Convener: Abhay Deshpande

15:00 The 25 years RHIC legacy of QCD

Speaker: Renee Fatemi (University of Kentucky)

Fatemi_DIS2026.pdf

15:30 DIS with ion beams: Ultra Peripheral Collisions

Speaker: Minjung Kim (CERN)

DIS2026_UPC_MJKIM_04May2026.pdf

16:00 Heavy-Ion Physics

Speaker: Alice Ohlson (Lund University)

dis2026_aohlson.pdf

16:30 → 17:00 Coffee break

17:00 → 18:30 Plenary 4

Convener: Barbara Badelek

17:00 Low-x, diffraction and forward physics

Speaker: Jonathan Hollar (LIP)

DIS2026_LowxDiffFwd_final.pdf

17:30 Spin and 3D structure: theoretical advances

Speaker: Markus Diehl (Deusches Elektronen-Synchrotron DESY)

Spin3D_thy.pdf

18:00 Spin and 3D structure: experimental results

Speaker: Silvia Niccolai (IJCLab)

DIS2026_Niccolai.pdf

19:00 → 20:00 Welcome reception

Tuesday 5 May

09:00 → 10:20 WG1 Structure functions and parton densities

Convener: Amanda Cooper-Sarkar

09:00 CT25: the new generation of CTEQ-TEA PDFs

I present the final release of the CT25 family of precision parton distributions in the nucleon and discuss phenomenological implications of the wide-ranging CT25 analysis for collider predictions and determination of the QCD coupling constant.

Speaker: Pavel Nadolsky (Michigan State University)

q505_dis2026.pdf

09:20 Towards a new NNPDF global analysis

We review progress and plans towards a new global PDF analysis from the NNPDF Collaboration. This new release will be based on state-of-the-art theory calculations, and in particular will be based on exact NNLO interpolation grids, (approximate) N3LO QCD corrections to DGLAP evolution and DIS structure functions, and QED effects to DGLAP evolution. All relevant sources of experimental and theoretical uncertainties, the latter including missing higher orders and higher twists, are taken into account. As compared to NNPDF4.0, this new release includes more than 25 new datasets from HERA jets to Drell-Yan (inclusive and with extra jets), top quark, and jet production at the LHC among others. Our machine learning methodology is statistically validated by extensive closure and future tests and benefits from an improve hyperoptimization algorithm.

Speaker: Felix Hekhorn (University of Jyväskylä)

talk-NNPDF.pdf

09:40 MSHT Updates

We provide an update of the MSHT parton distribution functions. We concentrate
on the impact of both new data sets and an improved theoretical and
statistical analysis for PDFs at high x values, including an investigation
of higher twist contributions. We also consider the potential impact of
Electron Ion Collider DIS data on PDFs, and in particular on the extraction
of the strong coupling constant, focussing on uncertainties from theoretical
sources. We also consider the impact of additional new data sets from the LHC.

Speaker: Robert Thorne (University College London)

DIS2026.pdf

10:00 Parton and nuclear dynamics at large x: the CJ26 global QCD analysis

We present the new CTEQ-JLab global QCD analysis, called CJ26, that simultaneously fits parton distribution functions of the proton and nuclear effects in deuteron targets. This work includes, for the first time in a global fit, the full set of JLab 6 GeV inclusive DIS measurements and the first published JLab 12 GeV data. The analysis focuses on the large-$x$ region, and carefully treats the interplay between higher-twist effects and off-shell corrections in low-energy proton and deuteron target data. We discuss their effect on quark and gluon distributions, and highlight the importance of quantifying the experimental correlated systematic uncertainty to achieve fits of the highest accuracy. We also  outline how upcoming data may help unravel the nuclear and partonic dynamics in light nuclei. The extracted next-to-leading order parton distributions will be provided in LHAPDF format for general use, accompanied by leading- and higher-twist structure functions calculated with the simultaneously fitted PDFs, higher-twist corrections, and off-shell corrections.

Speaker: Alberto Accardi (Christopher Newport U. and Jefferson Lab)

Alberto_Accardi - CJ26.pdf

09:00 → 10:45 WG2 Small-x, diffraction and vector mesons

Convener: Michael Pitt (CERN)

09:00 New ALICE results from Run 3 on exclusive dimuon production, coherent J/ψ and ψ(2S) photoproduction in ultra-peripheral Pb–Pb collisions

We present new measurements from the ALICE experiment on exclusive processes in ultra-peripheral Pb–Pb collisions at $\sqrt{s_{\mathrm{NN}}}~=~5.36$ TeV. The coherent photoproduction of ${\rm J} / \psi$ and $\psi({\rm 2S})$ is measured differentially in rapidity to probe nuclear gluon distributions at low Bjorken-$x$ $\sim$ $10^{-2}$. A significant suppression relative to the impulse approximation is observed, providing a clear evidence of nuclear shadowing. Simultaneously, the exclusive dimuon production $\gamma\gamma\to\mu\mu$, a pure QED process, is measured. These results serve as a critical benchmark, demonstrating high sensitivity to the precise modeling of the intense electromagnetic photon flux, particularly for photon impact parameters near the nuclear radius. Together, these measurements provide insights into nuclear PDFs and advance the understanding of strong-field QED in heavy-ion collisions.

Speaker: Nazar Burmasov (Joint Institute for Nuclear Research)

2026-05-05-DIS2026-ALICE-results-photoproduction-v4.pdf

09:20 Quarkonium photoproduction in peripheral heavy-ion collisions with ALICE

Ultrarelativistic heavy-ion collisions generate extremely strong electromagnetic fields that can induce photonuclear reactions. These processes have been extensively studied in ultraperipheral collisions (UPCs), where the impact parameter is larger than twice the nuclear radius. Recently, coherent J/$\psi$ photoproduction has also been observed in nucleus--nucleus (A--A) collisions with nuclear overlap, based on the measurement of an excess of J/$\psi$ production with respect to hadroproduction expectations at very low transverse momentum ($p_{\mathrm{T}}$). Such quarkonium measurements provide valuable insights into the nuclear gluon distribution at low Bjorken-$x$ and high energies. In addition, they offer a unique opportunity to investigate photon-induced reactions in A--A collisions with nuclear overlap, including possible interactions of the produced probes with the formed and rapidly expanding quark--gluon plasma.
To confirm the photoproduction origin of the very low-$p_{\mathrm{T}}$ J/$\psi$ yield excess, polarization measurements represent a golden observable. Due to $s$-channel helicity conservation, the produced quarkonium is expected to retain the polarization of the incoming photon. The ALICE experiment can measure inclusive and exclusive photo produced quarkonium down to zero transverse momentum, both at forward rapidity ($2.5 < y < 4$) and at midrapidity ($|y| < 0.9$).

In this contribution, Run~2 measurements of the rapidity($y$)-differential cross section and polarization of photoproduced J/$\psi$ mesons in peripheral Pb--Pb collisions at the LHC are presented. Both measurements are performed at forward rapidity in the dimuon decay channel. The results are discussed in the context of recent measurements of coherent J/$\psi$ photoproduction as a function of centrality at both midrapidity and forward rapidity. The current status and prospects of these studies in Run~3 are also discussed. Comparisons with available theoretical models are presented.

Speaker: Dukhishyam Mallick (Istituto Nazionale di Fisica Nucleare)

Photoproduction_JPSI_PC_ALICE_DIS2026_DM.pdf

09:40 Measurements of $J/\psi$ and the impact of coincident photon-induced processes in ultra-peripheral Pb+Pb collisions at $\sqrt{s_\mathrm{NN}}=5.36$ TeV with the ATLAS detector

In ultra-relativistic heavy-ion collisions, the Lorentz-contracted electromagnetic fields of the ions generate intense quasi-real photon fluxes. These can interact with photons emitted by the oncoming nucleus, or with the nucleus itself, either directly in inelastic processes or diffractively via pomeron exchange. Diffractive photo-nuclear processes can produce exclusive vector mesons that are uniquely sensitive to the spatial and momentum structure of the nuclear parton distribution functions, as well as spatial fluctuations (hot spots). In Run 3, the ATLAS experiment utilized a low-multiplicity track trigger in heavy ions for the first time, allowing the collection of a large sample of events with a few low momentum tracks. A substantial fraction of these are sensitive to di-lepton decays of vector mesons like the $J/\psi$. First results on $J/\psi$ yields, in association with various topologies of forward neutron emission will be presented using the widest continuous rapidity range available at the LHC. The high photon flux also enables the occurrence of multiple photon-induced processes in a single collision. This talk also presents the first measurement of coincident production of $\gamma\gamma \rightarrow \mu^{+}\mu^{-}$ and a $\rho$ meson in UPC Pb+Pb collisions at 5.02 TeV and 5.36 TeV with ATLAS. Scaling of the coincidence $\rho$ meson production rate with neutron topologies di-muon system's properties, such as its mass, are also presented. These results provide tighter constraints on photon fluxes and nuclear charge form factors, as well as insights into nuclear gluon PDFs, beyond those from inclusive $\rho$ meson photo-production.

Speaker: Agnieszka Ogrodnik (Institute of Nuclear Physics Polish Academy of Sciences)

DIS_2026.pdf

10:00 Probing Gluon Fluctuations in Nuclei using incoherent $\rm{J}/\psi$ photoproduction in PbPb at 5.02 TeV with the CMS experiment

The study of $\rm{J}/\psi$ photoproduction in ultra-peripheral collisions (UPCs) offers a powerful probe of gluon dynamics in heavy nuclei. In UPCs, photons can interact with the nucleus coherently (involving the entire nucleus) or incoherently (with individual constituents). While coherent processes provide insight into the average gluon density, incoherent photoproduction is uniquely sensitive to the local gluon density fluctuations at both nucleonic or subnucleonic levels. Thus, the systematic measurement of energy-dependent $\rm{J}/\psi$ photoproduction could explore the evolution of gluonic structures within nuclei in detail, with potential implications for uncovering the onset of gluon saturation at sufficient small-x regime.

In this talk, we present the first energy-dependent measurement of the incoherent $\rm{J}/\psi$ photoproduction cross section in PbPb UPCs at the LHC with the CMS experiment, using the forward neutron tagging to cover a wide photon-nucleon center-of-mass energy range from 40 to 400 GeV. This allows us to explore fluctuating gluon fields over a broad Bjorken-x range, extending into the uncharted region of x<10^-4. Furthermore, we report the ratio of incoherent to coherent \rm{J}/\psi$ production and evaluate the nuclear suppression factor for the incoherent production as a function of x. By comparing state-of-the-art theoretical predictions, these results offer unique insights into gluon fluctuations and have important implications for understanding nuclear gluon distributions and saturation phenomena.

Speaker: Shuai Yang (South China Normal University)

IncohJpsi_DIS2026_v2_sy.pdf

10:20 Studies of exclusive phi photoproduction and energy-dependent measurement of coherent rho^0 photoproduction in PbPb UPCs with the CMS Experiment

Photon-induced vector meson production in ultraperipheral heavy-ion collisions (UPCs) offers a unique and powerful probe of the gluon distribution in nuclei. The $\phi$ meson, with its mass around 1 GeV, lies at the boundary of hard scales between the perturbative and nonperturbative QCD regimes, making it uniquely suited to probe the transition between these two domains. Similarly, coherent vector meson photoproduction in UPCs of even lighter species such as the $\rho$ serves as a powerful tool for investigating the gluon structure of nuclei at small Bjorken-$x$, accessing lower energy scales with potential sensitivity to gluon saturation and nuclear shadowing. In this talk, the differential cross sections for coherent $\phi$ meson photoproduction a function of $\phi$ rapidity and the measurement of coherent $\rho^0$ photoproduction in Pb+Pb UPCs at $\sqrt{s_{NN}} = 5.36$ TeV with the CMS detector are presented.

Speaker: Pranjal Verma (IIT Madras)

DIS2026_Rho_Phi_Results.pdf

09:00 → 10:45 WG3 Electro-weak physics/higgs/top and BSM: Top Physics 1

Conveners: Ken Mimasu (University of Southampton), Menglin Xu

09:00 Highlights on top quark properties and mass measurements with the ATLAS detector (17'+3')

The top-quark mass is one of the key fundamental parameters of the Standard Model that must be determined experimentally. Its value has an important effect on many precision measurements and tests of the Standard Model. In this contribution, the top quark mass measurements by the ATLAS experiment are reviewed. In addition, new results on top-quark properties are shown.

Speaker: Alberto Prades (Istituto Nazionale di Fisica Nucleare)

PradesAlberto_DIS2026_050526.pdf

09:20 Measurements of top quark production and its properties (17'+3')

Precision measurements of top quark properties are of paramount importance for our understanding of the SM. We present several measurements of cross section top quark production and of its properties, including asymmetries and spin correlations. These measurements allow us to test the fundamentals of quantum mechanics at the highest energies achieved so far and also serve as an excellent probe for physics beyond the Standard Model.

Speaker: Javier Cuevas (Universidad de Oviedo (ES), ICTEA)

top_dis26_may26.pdf

09:40 Spin Correlations in ttbar Production and Decay at the LHC in QCD Perturbation Theory (17'+3')

We consider the QCD predictions for spin correlations in ttbar production at the LHC and argue that, for the observables usually considered for searches close to threshold production, it is possible to perform the calculation using perturbation theory, considering only the contributions that scale as the first few powers of alphas/v. Implementing such strategy to correct nominal Monte Carlo results for correlation-sensitive observables, we show that results obtained are compatible with data, and, more specifically, that the contribution from ttbar bound states (toponium), while being present also in our study, does not seem to be crucially important to get agreement with data.
The content of the talk will be based mostly on https://arxiv.org/abs/2505.00096

Speaker: Emanuele Re (Istituto Nazionale di Fisica Nucleare)

2026_05_05_DIS_v2_fixed_typos.pdf

10:00 ttbar cross section, including threshold and off-shell measurements (17'+3')

The exceptionally large dataset collected by the ATLAS detector at the highest proton-proton collision energies provided by the LHC enables precision testing of theoretical predictions using an extensive sample of top quark events. This wealth of data has opened the door to new measurements of top quark properties including those particularly sensitive to the ttbar threshold region. This contribution presents the latest highlights in the top quark cross-section measurements, including the production threshold measurements, from the ATLAS quark physics.

Speaker: Nello Bruscino (NA)

Bruscino.DIS2026.TopThresholdATLAS.pdf

09:00 → 10:45 WG4 QCD with Heavy flavours and Hadronic Final States

09:00 Massive charm contribution in large-x resummation to $F_2^c$ for CC DIS

Deep inelastic scattering has always represented a fundamental tool for probing the internal structure of nucleons and the dynamics of quarks and gluons; hence, huge efforts are constantly made by the entire community to increase the level of accuracy in DIS-related theoretical predictions.
In this talk I discuss the impact of $c$-quark mass effects to $F_2^c$ in charge current DIS, presenting NLO accurate predictions supplemented with soft-gluon resummation at NLL’ for this observable. The analysis is performed by employing a new framework which allows to interpolate between massless and massive scheme, including $\mathcal{O}(\alpha_S)$ contributions that do not vanish in the large-$N$ limit, therefore allowing to consistently resum both mass and soft logarithms.

Speaker: Lorenzo Mai (University of Genova & INFN)

LM_DIS_2026.pdf

09:20 NNLO results for heavy quark Charged DIS

The contribution of quarks with masses m ≫ ΛQCD is the only part of the structure functions in charged deep-inelastic scattering (DIS) which is not yet known at the next-to-next-to-leading order (NNLO) of perturbative QCD. We present improved NNLO results for the most important structure function F2(x, Q^2). We compute the corrections coming from the real-virtual and double real emission subprocesses. We employ the method of differential equations to solve the phase space integrals.

Speaker: Pooja Mukherjee (University of Bonn, Germany)

DIS_2026.pdf

09:40 Results from the DsTau (NA65) experiment at CERN-SPS

The DsTau (NA65) experiment at CERN is designed to measure the inclusive differential cross section for $D_s$-meson production in proton–nucleus (p–A) interactions, where the $D_s$ meson decays into a tau lepton and a tau neutrino. The DsTau detector is based on the nuclear emulsion technique, which provides exceptional spatial resolution and enables precise detection of short-lived particles such as charmed hadrons. In this presentation, we report the first results from the analysis of pilot-run data, with particular emphasis on the performance of proton interaction vertex reconstruction in high track-density environments. The collected data are compared with predictions from several Monte Carlo event generators. The current status of the $D_s$ search is also presented.

Speaker: Canay Öz

05_05_2026_DIS_DsTau.pdf

10:00 New D-meson fragmentation functions from LEP and LHC

We discuss a new extraction of D-meson fragmentation functions using experimental data from LEP and LHC. We focus particularly on kinematical regimes where perturbative QCD should be safely applicable to avoid contamination from higher-twist effects which could lead to an apparent process dependence of fragmentation functions. We account for the initial-state radiation and, as a novel ingredient, consider the prompt and non-prompt contributions separately. The analysis is carried out at next-to-leading order accuracy for $D^0$, $D^\pm$, and $D^*$ mesons, including uncertainty estimation based on Monte-Carlo replica technique.

Speaker: Felix Hekhorn (University of Jyväskylä)

talk-hymn.pdf

10:20 sPHENIX measurements of heavy flavor and strangeness production in p+p collisions at RHIC

The new sPHENIX collider detector experiment features a unique tracking system capable of streaming readout, enabling the collection of very large, unbiased p+p datasets previously not available at RHIC. In two running periods during 2024 and 2025, sPHENIX collected over 14pb$^{-1}$ of unbiased pp collisions using the novel streaming readout capabilities of the tracking subsystems. This enables precise measurements of a wide variety of strange light and heavy flavor hadrons that can yield insight on hadron formation. In particular these measurements are sensitive to effects from color reconnection, hadronization mechanisms, and co-movers. This talk will present progress towards measurements at RHIC of strange and heavy flavor hadron ratios in p+p collisions, highlighting the unique capabilities enabled by streaming readout data collection.

Speaker: Alexander Patton

PattonDIS2026.pdf

09:00 → 10:45 WG5 Spin and 3D-structure

Convener: Matteo Cerutti

09:00 Recent results on transverse-momentum–dependent distributions from the MAP collaboration

Recent results on the determination of transverse-momentum–dependent parton distributions obtained within the MAP collaboration will be presented. The focus will be on the flavor dependence of unpolarized TMDs and on updated extractions of the helicity TMD, highlighting the constraints provided by current experimental data and their phenomenological implications. The role of machine-learning techniques in improving the flexibility and robustness of TMD analyses will be discussed.

Speaker: Alessandro Bacchetta (Istituto Nazionale di Fisica Nucleare)

Bologna_DIS2026_Bacchetta.pdf

09:20 Phenomenological estimate for the longitudinal structure function in SIDIS

Obtaining a unified description of the transverse-momentum spectrum of hadrons produced in SIDIS through the $W+Y$ construction has been a primary focus within the nuclear physics community the last few decades. A critical element of this framework is the matching between low- and high-$q_T$ structure functions. While some unpolarized SIDIS structure functions match consistently at leading power, others do not, although recent studies suggest that subleading contributions may be phenomenologically relevant. In this work, we investigate the impact of such effects by studying the ratio $R_{\rm SIDIS} = F_{UU,L}/F_{UU,T}$, for which the longitudinal structure function $F_{UU,L}$ is purely sub-leading in the low-$q_T$ region, making this observable a sensitive probe of next-to-leading-power dynamics in the unpolarized sector. We implement various models which induce a sub-leading $F_{UU,L}$ and study their impact on predictions for $R_{\rm SIDIS}$. Our results highlight the importance of sub-leading effects as well as a consistent treatment of the transverse momentum spectrum for the prediction of $R_{\rm SIDIS}$.

Speaker: Richard Whitehill (Old Dominion University / Jefferson Lab)

DIS2026-WG5_RWhitehill.pdf

09:40 A Bayesian Pixel Based Approach for Model Independent TMD Reconstruction

The extraction of Transverse Momentum Dependent distributions (TMDs) from experimental observables represents a classic inverse problem in hadronic physics. Traditionally, this challenge is addressed by assuming specific analytical functional forms, which can introduce inherent parameterization bias and limit the exploration of the full epistemic uncertainty.

In this talk, we present a novel "Pixel-Based" approach that conceptualizes TMD imaging as a discrete image reconstruction task. By formulating the TMD convolutions through discrete tensor algebra, we treat each pixel in the impact parameter ($b_T$) space as a stochastic variable. This framework allows us to perform a non-parametric reconstruction of the TMDs within a robust Bayesian inference scheme. To efficiently sample the high-dimensional posterior distribution of the pixels, we employ modern Machine Learning techniques, specifically Normalizing Flows.

We focus on a systematic study of the resolution limits and stability of this inversion process. By analyzing the resolution matrix in $b_T$-space, we quantify how different kinematic coverages and experimental precision constrain the underlying 3D structure. Furthermore, we provide a comparative analysis between standard analytical parameterizations and our pixel-based approach to quantify the systematic bias introduced by fixed functional forms. This work serves as a proof-of-concept for a low-bias imaging framework, establishing a robust foundation for model-independent extractions of nucleon structure.

Speaker: Marco Zaccheddu (Jefferson Lab)

DIS26_mz_slides.pdf

10:00 COMPASS contribution to the study of the three-dimensional structure of the nucleon in SIDIS

Over more than 20 years of data taking, the COMPASS fixed-target experiment at the CERN SPS has devoted a major part of its programme to the study of nucleon structure using high-energy muon and pion beams and proton and deuteron targets. In particular, SIDIS measurements with transversely polarised and unpolarised targets, performed in a unique kinematic domain, have provided key insights into the transverse-spin and transverse-momentum structure of the nucleon and continue to deliver essential input for multidimensional studies.
This presentation gives an overview of the COMPASS SIDIS measurements with transversely polarised proton and deuteron targets, and discusses the results expected from the deuteron data set collected in 2022. In addition to the “standard” single-hadron and di-hadron asymmetries, novel measurements that go beyond these channels will be reviewed and discussed.

Speaker: Anna Martin (Istituto Nazionale di Fisica Nucleare)

Martin_DIS2026.pdf

10:20 SIDIS studies at ePIC

Semi-Inclusive Deep Inelastic Scattering (SIDIS) is a key component of the physics program of the future Electron--Ion Collider (EIC), providing multidimensional access to the internal structure of nucleons and nuclei. Through measurements of hadron transverse momentum and azimuthal modulations, SIDIS enables detailed studies of parton dynamics, transverse-momentum--dependent (TMD) structure functions, and hadronization mechanisms in the deep-inelastic scattering regime. These observables are directly relevant for the extraction of parton densities and TMDs, and place stringent requirements on detector acceptance, momentum resolution, particle identification, and control of experimental backgrounds.

The ePIC detector, the reference experiment for the EIC, has been designed as a general-purpose apparatus optimized to meet these challenges. Its nearly hermetic coverage, high-precision tracking and vertexing, and comprehensive particle identification systems provide the experimental foundation for precision SIDIS measurements over a broad kinematic range in Bjorken-$x$, momentum transfer $Q^2$, hadron momentum, and rapidity.

In this contribution, we present SIDIS performance studies for ePIC based on full detector simulations. Different methods for reconstructing SIDIS kinematics, including electron-based and hadron-based approaches, are discussed and compared in terms of resolution and stability across the relevant phase space. The resulting performance on key variables such as $x$, $Q^2$, the hadron energy fraction $z$, and the hadron transverse momentum $P_{hT}$ is quantified, highlighting regions of enhanced sensitivity to detector performance.

We focus on benchmark SIDIS measurements central to the DIS physics program, including charged-hadron multiplicities and azimuthal modulations sensitive to TMD dynamics. The role of particle identification is emphasized, demonstrating the combined performance of time-of-flight and Ring Imaging Cherenkov detectors in achieving efficient pion, kaon, and proton separation over a wide momentum range. This capability is essential for flavor-separated SIDIS measurements and for extending the kinematic reach toward forward rapidities.

These studies demonstrate that ePIC satisfies the experimental requirements of the SIDIS program at the EIC and will enable high-precision DIS measurements in future experimental campaigns.

Speaker: Susanna Costanza (Istituto Nazionale di Fisica Nucleare)

DIS26_CostanzaSusanna_v5.pdf

09:00 → 10:28 WG6 Current upgrades and future experiments

Convener: Lesya Shchutska (EPFL)

09:00 Particle physics at the BNL electron-ion collider

High-Energy (HEP) and Nuclear Physics (NP) experiments are becoming more and more similar in so far as accelerator and detector technologies, experimental techniques, scientific programs as well as communities. More specifically, there is a very successful cross-fertilization between the Large Hadron Collider (LHC) and the Electron Ion Collider (EIC) experiments. The EIC at Brookhaven National Laboratory (BNL) is the only major collider experiment planned so far on the US soil and will start operations in the mid-2030s. The LHC will run in parallel at CERN with High Luminosity (HL-LHC) until 2041, while a future Higgs boson factory is expected to start in the mid-2040s. While the EIC physics goals are primarily focused on understanding the constituents of matter and their interactions inside the atomic nuclei, its program extends beyond that, including measurements of electroweak processes and searches for new physics that are complementary in reach to those at the LHC. Several experimental techniques developed for the LHC experiments, including for example jet substructure and Machine Learning, will be beneficial for harvesting the EIC data too. Furthermore, the detector R&D for the EIC experiments goes hand-in hand with the one for the CERN’s Future Circular Collider with electron and positron beams (FCC-ee) as well as with the HL-LHC detector upgrades. For example some detector technologies that were pioneered for the HL-LHC detectors upgrades will be also applied, modified and improved for EIC experiments, and these are in turn planned to be used at FCC-ee experiments. Because of this interdependence between HEP and NP experiments, the two communities are more and more overlapping. This talk will highlight the physics reach of EIC experiments and the strong links with HEP experiments.

Speaker: Alessandro Tricoli (Brookhaven National Laboratory)

Tricoli_EIC_DIS26-May2026.pdf

09:20 QCD at the LHeC

The Large Hadron electron Collider (LHeC) is the proposal to deliver electron-proton/nucleus collisions at CERN using the LHC beams and a 50 GeV electron beam from an Energy Recovery Linac. While initially foreseen [1] for concurrent electron-hadron and hadron-hadron operation, a standalone electron-hadron operation phase has been proposed [2] in view of the current LHC schedule. Thus, the LHeC becomes a bridge from the HL-LHC to the next flagship at CERN, and one of the possible projects in the 2026 Update of the European Strategy for Particle Physics [3], were the FCC-ee as plan A not feasible.
In this talk we review the QCD studies at the LHeC. The impact of DIS on the extraction of parton densities of proton and nuclei and on the determination of $\alpha_s$ is analysed. The implications for such extraction on EW parameters and Higgs couplings at the HL-LHC, and on the extension of high-mass searches, is discussed. The combination with EIC data is also shown. Finally, the possibilities for unraveling the existence of a new non-linear regime of QCD are discussed.
[1] P. Agostini et al. (LHeC/FCC-he Study Group), J. Phys. G 48, 110501 (2021), arXiv:2007.14491 [hep-ex].
[2] F. Ahmadova et al., e-Print: 2503.17727 [hep-ex].
[3] The European Strategy for Particle Physics: 2026 Update - Recommendations by the European Strategy Group, https://cds.cern.ch/record/2950671/files/CERN-ESU-2025-002.pdf?version=1.

Speaker: Dr Francesco Giuli (Istituto Nazionale di Fisica Nucleare)

FGiuli_LHeC_DIS26.pdf

09:40 A detector for top energy DIS

The Large Hadron electron Collider (LHeC) is the proposal to deliver electron-proton/nucleus collisions at CERN using the LHC beams and a 50 GeV electron beam from an Energy Recovery Linac. While initially foreseen [1] for concurrent electron-hadron and hadron-hadron operation, a standalone electron-hadron operation phase has been proposed [2] in view of the current LHC schedule. Thus, the LHeC becomes a bridge from the HL-LHC to the next flagship at CERN, and one of the possible projects in the 2026 Update of the European Strategy for Particle Physics [3], were the FCC-ee as plan A not feasible.
In this talk we review the status of the design of a detector for the LHeC, and its extension to the FCC-eh. We present the present technology choices with their expected performance. We also analyse the possible synergies with future projects like ePIC, ALICE3 and detectors for $e^+e^-$ colliders. Finally, we review the feasibility and cost of such a detector.
[1] P. Agostini et al. (LHeC/FCC-he Study Group), J. Phys. G 48, 110501 (2021), arXiv:2007.14491 [hep-ex].
[2] F. Ahmadova et al., e-Print: 2503.17727 [hep-ex].
[3] The European Strategy for Particle Physics: 2026 Update - Recommendations by the European Strategy Group, https://cds.cern.ch/record/2950671/files/CERN-ESU-2025-002.pdf?version=1.

Speaker: Dr Laurent Forthomme (AGH University of Kraków (PL))

lhec_detector_forthomme_dis.pdf

10:00 The IDEA detector concept for FCC-ee

The future circular electron-positron collider (FCC-ee) has been outlined as the recommended priority for the next collider at CERN by the EU strategy update process. We present IDEA, a detector concept optimized for FCC-ee and composed of a vertex detector based on DMAPS (Depleted Monolithic Active Pixel Sensors), a very light drift chamber, a silicon wrapper, a crystal electromagnetic calorimeter readout in dual readout mode, a thin 3 Tesla HTS (High Temperature Superconductor) solenoid, a dual readout hadronic fibre calorimeter and muon chambers placed within the magnet yoke. In particular we discuss the physics requirements and the technical solutions chosen to address them. The IDEA detector is a concept under development and we present some possible upgrades that are being studied in order to further extend and improve the physics capabilities of IDEA. We then describe the detector R&D currently in progress and show the expected performance on some key physics benchmarks.

Speaker: Iacopo Vivarelli (Istituto Nazionale di Fisica Nucleare)

VIvarelli_DIS2026_05052026.pdf

10:20 Simulation based performance of the ePIC-dRICH for Forward PID at the Electron Ion Collider

The future Electron Ion Collider (EIC) in BNL, USA, will be the ultimate facility to study Quantum Chromodynamics (QCD) with an unprecedented accuracy. The ePIC detector is a general purpose detector, capable of providing the entire physics programme documented in the EIC Yellow report. The requirements for the EIC accelerator and the ePIC detector are challenging. In the EIC highly polarized electrons (~70%) will be colliding with highly polarized nucleons and light nuclei (~70%); unpolarized nuclei can be as heavy as Uranium nuclei. The centre-of-mass energy for such collisions will vary from 20 GeV to 140 GeV with peak luminosity reaching 10$^{33}$-10$^{34}$ cm$^{-2}$ s$^{-1}$.
The forward (hadron going) direction is characterized as the high x-Q$^2$ region, therefore in this region the majority of the high momentum hadrons will be produced. An efficient identification of those high momentum charged hadrons is essential to several key physics channels. A dual Radiator Ring Imaging Cherenkov (dRICH) counter will perform the identification of the high momentum charged hadrons. Furthermore, it will also be used to reject low momentum pions from electrons to complement the Calorimeter in reconstructing the Deep Inelastic Scattering (DIS) events. By providing charged pion–kaon separation from approximately 3 GeV/c up to 50 GeV/c (and even higher for kaon–proton separation) and electron–pion separation from a few hundred MeV/c up to 15 GeV/c, with at least 3 σ separation over a wide pseudorapidity range (1.5 < η < 3.5), the dRICH will serve as a cornerstone for the successful Semi-Inclusive DIS (SIDIS) programme of the ePIC collaboration.
The design of the dRICH faces several challenges coming from the global detector: shorter radiator length, presence of the solenoidal magnetic field of the ePIC detector and high radiation in the sensor region. A set of thorough and systematic simulation studies are essential to overcome these challenges and to deliver an optimal design that provides the ambitious physics requirements.
In this contribution we describe the realistic geometric model, optical parameters for the sensors and the two radiators used in the simulation studies as well as impact of noise in the detector performance. The simulation has been performed using the official simulation framework of the ePIC collaboration. We also present the identification and confusion matrix obtained from these studies. The simulation framework is capable of providing not only the detector performance used in physics studies, but also several microscopic design features that allow us to optimize the detector parameters and mitigate the design risk. Incorporation of a Bayesian optimization serves as an important tool to perform such detector optimization. We also introduce an AI/ML based algorithm involving Convoluted Neural Network (CNN) for future application for the dRICH PID.

Speaker: Ramandeep Kumar (Istituto Nazionale di Fisica Nucleare, Sezione di Trieste)

Slides_DIS-2026_RamandeepKumar_dRICHsimuation.pdf

10:45 → 11:00 Coffee break - available from 10:30 to 11:30

11:00 → 13:00 WG1 Structure functions and parton densities

Convener: Robert Thorne (University College London)

11:00 Correlations in theory uncertainties from missing higher orders

Properly estimating theory uncertainties from missing higher orders is notoriously a challenging task. Controlling correlations among them is even more challenging. However, these correlations are crucially important for analysing experimental data.
Building upon recent progress in the topic, we propose a novel approach that takes advantage of different methods to provide a reliable and robust construction of correlations among theoretical predictions.

Speaker: Marco Bonvini (Istituto Nazionale di Fisica Nucleare)

bonvini_MHOUcorrelations_DIS2026.pdf

11:10 Exploring Parametrization and Prior Biases for CT PDFs

We present a study of parametrization dependence in the construction of the CT25M PDF uncertainty prescription. This prescription is informed by preliminary analyses within the CT collaboration, including investigations of general polynomial approximators for PDF modeling, statistical interpretations of model combination, and characterization of the solution space via clustering and information criteria. We summarize the key ingredients of this framework and review related studies within the CT group.

Speaker: Aurore Courtoy (Instituto de Física, UNAM)

DIS_26_AC.pdf

11:20 Theory updates for parton distributions in Hessian formalism

We present a new extension to the toolbox of parton-distribution reweighting methods, which enables a general user to study the impact of an updated theory prediction on the results of a pre-existing parton-distribution global analysis. This new method is a combination of the well-known reweighting method with a new deweighting variant where a dataset is removed from the original analysis in an approximative way. Specific use cases of this method could include e.g. testing the impact of updating the treatment of an observable from NnLO to Nn+1LO precision in the global analysis, or of including previously ignored electroweak, mass, or higher-twist effects, or even testing the impact of some beyond-standard-model physics. We discuss the implementation of this method in the Hessian formalism, and show its use in a single case study.

Speaker: Petja Paakkinen (CERN)

DIS_2026_Paakkinen.pdf

11:30 Colibri: a new tool for fast-flying PDF fits

Despite its ability to quantify uncertainties probabilistically and naturally accommodate theoretical constraints, Bayesian inference has so far played a limited role in PDF fitting. In this talk I will present Colibri, an open-source code that provides a general and flexible tool for PDF fits. The code is built so that users can implement their own PDF model, and use built-in functionalities for a fast computation of observables. It grants easy access to experimental data, several error propagation methodologies, including the Hessian method, the Monte Carlo replica method, and an efficient numerical Bayesian sampling algorithm. To demonstrate the capabilities of Colibri, I will present a simple application: a polynomial PDF parametrisation. I further discuss how the functionalities illustrated in this example can be extended to more complex PDF parametrisations. In particular, Bayesian sampling in Colibri provides a framework for systematic model selection and model averaging, making it a valuable tool for benchmarking and combining different PDF parametrisations on solid statistical grounds.

Speaker: Valentina Schutze (University of Cambridge)

DIS2026-presentation.pdf

11:40 Markov Chain Monte Carlo analysis of parton distribution functions

We present the application of Makov Chain Monte Carlo (MCMC) method to analysis of parton distribution functions (PDFs). The MCMC approach naturally implements Bayes' theorem, hence provides a means to directly sample the underlying probability distribution - in this case the probability distribution of the PDF parameters. This allows for a straightforward propagation of the resulting uncertainties into any PDF-dependent observable, preserving their simple probabilistic interpretation. We show that the flexibility of the Bayes framework, allowing e.g. to account for non-Gaussianity, inconsistencies of data sets, or multiple minima, is crucial to extract realistic uncertainties when such assumptions are not fulfilled. The method is successfully applied in two cases: to determine proton and nuclear PDFs.

Speaker: Aleksander Kusina (Institute of Nuclear Physics Krakow)

kusina_DIS2026.pdf

12:00 Neural Network Reconstruction of Parton Distributions from Lattice QCD

We propose a framework for the reconstruction of parton distribution functions (PDFs) and generalized parton distributions (GPDs) from lattice QCD, utilizing artificial neural networks (ANNs). Our approach combines two complementary methodologies: the Large Momentum Effective Theory (LaMET) and the short-distance operator expansion (SDE). To determine ANN-based PDFs and GPDs, we achieve a joint reconstruction that incorporates quasi-matrix elements from LaMET and matched Ioffe-time distributions derived from SDE. Our framework successfully recovers PDFs and GPDs from mock data and is applied for actual lattice QCD data. It mitigates the individual limitations inherent in LaMET and SDE, while leveraging the ANN architecture to enable a robust reconstruction.

Speaker: Min-Huan Chu (Adam Mickiewicz University, Poznań)

Lattice_ANN.pdf

12:20 What Can Lattice QCD Tell Us About Sea-Quark Asymmetry?

The flavor asymmetry of the partonic sea offers important insight into the nonperturbative structure of hadrons and the underlying dynamics of QCD. Recent methodological advances in lattice QCD (LQCD) have enabled direct access to the Bjorken-x dependence of hadronic structure, overcoming the long-standing limitation of lattice calculations to a small number of distribution moments. In this talk, I will present a new LQCD result obtained directly at the physical pion mass and provide comparisons with existing phenomenological extractions of sea-quark asymmetry.

Speaker: Huey-Wen Lin (Michigan State University)

antiquark asymmetry from LQCD

12:40 Higher Moments of Parton Distribution Functions from Lattice QCD at the Physical Point

Using the standard tools of Euclidean lattice QCD, we present a determination of the third Mellin moments $\left<x^2\right>$ of nucleon's unpolarized, polarized and transversity parton distribution functions.
Two lattice QCD ensembles at the physical pion mass are used: these were generated using a tree-level Symanzik-improved gauge action and $2+1$ flavor tree-level improved Wilson Clover fermions coupling via 2-level HEX-smearing.
Leveraging a wide set of interpolating operators, two extraction methods for the matrix elements, data driven priors to control excited states in multi-states fits, and the automatic inclusion of model uncertainties via bootstrapped model averages, we are able to extract values of the third Mellin Moments that we can compare to previous lattice and phenomenological results.
The data analysis procedure is explained and the obtained results are discussed.

Speaker: Emilio Taggi (Forschungszentrum Jülich, Bonn University)

EmilioTaggi_DIS2026.pdf

11:00 → 13:00 WG3 Electro-weak physics/higgs/top and BSM: Top Physics 2

Conveners: Ken Mimasu (University of Southampton), Menglin Xu

11:00 Measurements of top quark associated production and rare processes (17'+3')

Precision measurements of top quark production cross sections are crucial for validating the Standard Model and investigating potential new physics. In this talk, we present both inclusive and differential measurements of top quark production in association vector bosons and other rare processes. Such measurements are used to set limits on new physics contributions affecting the interactions between the top quark and other SM particles.

Speaker: Victor Rodriguez Lorenzo (Universidad de Cantabria and CSIC (ES))

VRL-TopRareProcesses_DIS2026.pdf

11:20 Overview of EFT-based searches involving top quarks at ATLAS (17'+3')

Many-parameter fits to precise measurements in the framework of the Standard Model Effective Field Theory are becoming a standard interpretation of LHC and other collider data. In this contribution an overview is given of state-of-the-art EFT interpretations in ATLAS with particular emphasis on results in the top quark sector.

Speaker: Barbora Eckerova

Overview of EFT-based searches involving top quarks at ATLAS_final.pdf

11:40 Two-loop amplitude for the associated production of a top-anti-top pair and a W boson at hadron colliders (17'+3')

In this talk I will present the first exact calculation of the leading-colour two-loop QCD amplitude for the associated production of a top-anti-top pair and a W boson. I will discuss strategies to address the complexity of the computation, which involves complicated analytic structures, such as nested square roots, elliptic functions, and expressions with a high degree of algebraic complexity. The final result is expressed in terms of a set of special functions, which are evaluated using the method of differential equations, and rational coefficients, evaluated via finite field techniques.

Speaker: Mattia Pozzoli (Istituto Nazionale di Fisica Nucleare)

DIS2026_MP.pdf

12:00 Multi-scale improved predictions for $pp \to t\bar{t}W^+ (j)$ (17'+3')

In this presentation, I will talk about the Multi-scale improved NLO (MINLO) method as an alternative to the standard fixed-order NLO approach. The MINLO method, which is now implemented in the HELAC-NLO framework, depends on an arbitrary choice of renormalization and factorization scales. This approach dynamically determines these scales based on the most probable branching histories and incorporates Sudakov form factors to resum large double logarithms that arise in processes with widely separated energy scales. I will present the differences between the two approaches through a comparative study of the full off-shell $pp \to t\bar{t}W^+ + \rm jets$ processes at NLO in QCD. Merging of the $pp \to t\bar{t}W^+ + \rm jets$ samples with up to 2 jets, that can improve the overall accuracy of the full off-shell $pp \to t\bar{t}W^+ + X$ predictions, will also be discussed.

Speaker: Nikolaos Dimitrakopoulos (RWTH Aachen University)

DIS2026 - Bologna.pdf

12:20 Modeling top-quark decays in $t\bar{t}t\bar{t}$ production at the LHC (8')

In this talk I present NLO QCD predictions for the $pp\to t\bar{t}t\bar{t}+X$ process in the 4 lepton decay channel at the integrated and differential level for the LHC centre-of-mass energy of $\sqrt{s}=13.6$ TeV. Specifically I compare the fixed order NLO QCD calculations to the parton-shower matched results obtained with MC@NLO and POWHEG matching. In the former, NLO QCD corrections are consistently included in the production and decay of the four top quarks, preserving all spin correlations. In the latter, higher order effects in top-quark decays with approximate spin correlations are simulated in the parton showers, using Pythia. Additionally I analyse the impact of including matrix element corrections in the top quark decays in the parton-shower matched predictions.

Speaker: Manal Alsairafi (RWTH Aachen University)

DIS33_Alsairafi.pdf

12:28 Complete NLO corrections to full off-shell $t \bar{t}$ production in the $\ell+j$ decay channel (8')

I will present results for the complete next-to-leading-order (NLO) corrections to full off-shell top-quark pair production in the $\ell+j$ decay channel, $pp \to \ell^- \bar{\nu}_\ell\, j_b j_b \, jj + X$, with $\ell^- = e^-,\, \mu^-$. The calculation consistently includes finite-width effects of the top quarks and $W^\pm/Z$ gauge bosons, as well as all doubly-, singly-, and non-resonant contributions and their interferences. All Born-level contributions, spanning perturbative orders from ${\cal O}(\alpha_s^4\alpha^2)$ to ${\cal O}(\alpha_s^0\alpha^6)$, are corrected by both NLO QCD and NLO electroweak effects, and all relevant partonic initial states and decay channels are taken into account.
I will briefly discuss infrared-safe treatments of photons and jets, based on parton-to-photon fragmentation and photon-to-jet conversion functions. Results are shown for integrated and differential fiducial cross sections at the LHC Run III energy of $\sqrt{s}=13.6$ TeV, including an assessment of subleading NLO effects such as electroweak Sudakov logarithms and non-resonant QCD backgrounds. Two analysis strategies, with and without a resonance-enhancing cut on the light-jet invariant mass, $|M_{jj}-m_W|<{\cal Q}_{cut}=20$ GeV, are compared to illustrate their impact on background suppression and off-shell effects.

Speaker: Leon Mans (RWTH Aachen University)

LeonMans_DIS2026.pdf

11:00 → 12:56 WG6 Current upgrades and future experiments

Convener: Domenico Elia (Istituto Nazionale di Fisica Nucleare)

11:00 CLAS12 experiments with a transversely polarized target

In the recent years, it has been realized that deep-inelastic scattering with polarization control could provide a variety of spin and azimuthal angle dependent observables sensitive to the quark-gluon interactions. New parton distributions and fragmentation functions have been introduced to describe the rich complexity of the hadron structure and move towards a multi-dimensional imaging of the underlying parton correlations. Besides the hard probe scale, these functions explicitly depend on the parton transverse degrees of freedom at the scale of confinement. Their study promises to open a unprecedented gateway to the peculiar nature of the strongly interacting force.

The CLAS12 experiments with a transversely polarized target (Run-Group H, or RGH) will have a unprecedented sensitivity to several crucial observables whose current knowledge is severely limited by the sparse data available. Distinctive features, common to all three RGH experiments, are the precise measurement of parton distributions and phenomena in the poorly explored valence region (large Bjorken-x) where current models project their magnitude to be peaking, a luminosity at least one order of magnitude higher than the previous experiments, a large acceptance detector for the disentanglement of the various correlations and kinematic regimes, and an excellent particle identification capability to access flavor sensitivity.

This work presents a selection of upcoming measurements planned at CLAS12 to address the mysteries of the nucleon structure from a modern point of view.

Speaker: Marco Contalbrigo (Istituto Nazionale di Fisica Nucleare)

SPIN_260505.pdf

11:20 LHuC: A high energy, high luminosity muon-hadron collider at CERN

The latest developments concerning the possibility of making muon-hadron collisions by reusing the ERL infrastructure, proposed for the LHeC, will be presented. At the LH$\mu$C, a 500 GeV $\mu^+$ beam will be colliding with a 7 TeV proton beam, resulting in the centre-of-mass energy $\sqrt{s}=3.74$ TeV (higher than at the FCC-eh), with the expected luminosity above $10^{33}$cm$^{-2}$s$^{-1}$.

First half of the talk will be dedicated to the discussion of the LH$\mu$C concept – from the ultra-cold $\mu^+$-source, through the muon booster, to the main muon ring. Initial considerations regarding the machine-detector interface and the general-purpose detector will be also presented. In the second half, an overview of the LH$\mu$C scientific programme will be given, with highlights from QCD, through the Higgs-Electroweak-Top (HET) sector, to the beyond Standard Model case. The talk will conclude with a short discussion of unique and powerful synergies between the LH$\mu$C, LHeC, Muon Collider and FCC projects.

Speaker: Prof. Krzysztof Piotrzkowski (AGH University)

Bologna_KP.pdf

11:40 LHCspin: a polarized fixed-target system at the LHC

Understanding the complex structure of nucleons in terms of quarks and gluons represents one of the most pivotal and contemporary challenges in particle physics. A significant advancement has been made through measurements accessing their multi-dimensional structure, crucial for gaining new insight into the strong interaction in the non-perturbative regime of QCD, as well as for opening new physics frontiers. The LHCspin project aims to precisely investigate the 3D structure of the proton and to perform spin physics studies via high-energy polarized fixed-target collisions, exploiting new probes and exploring new processes in a unique kinematic regime. The project will be developed in two phases. The first phase focuses on an innovative R&D program in the LHC Interaction Region 4 with the possibility to already perform unique exploratory measurements. The second phase aims at the installation of a polarized gas target in front of the LHCb spectrometer, bringing spin physics to the LHC for the first time. This builds on the installation of SMOG2, an unpolarized gas target that made LHCb the first experiment capable of acquiring data simultaneously in the collider mode at $\sqrt{s_{NN}}=14\;$TeV and in the beam-target mode at $\sqrt{s_{NN}}=100\;$GeV. The current status of the LHCspin project is presented along with its scientific potential and experimental setup.

Speaker: Anna Piccoli (University of Ferrara, Istituto Nazionale di Fisica Nucleare - Sezione di Ferrara)

DIS26_Piccoli.pdf

12:00 Top and EW physics at the LHeC

The Large Hadron electron Collider (LHeC) is the proposal to deliver electron-proton/nucleus collisions at CERN using the LHC beams and a 50 GeV electron beam from an Energy Recovery Linac. While initially foreseen [1] for concurrent electron-hadron and hadron-hadron operation, a standalone electron-hadron operation phase has been proposed [2] in view of the current LHC schedule. Thus, the LHeC becomes a bridge from the HL-LHC to the next flagship at CERN, and one of the possible projects in the 2026 Update of the European Strategy for Particle Physics [3], were the FCC-ee as plan A not feasible.
In this talk we review the EW and top physics studies at the LHeC. We present new results on the extraction of the Weinberg angle and top, Z and W masses, together with the impact of the improved determination of PDFs+$\alpha_s$ at the LHeC on their extraction at the HL-LHC. We also present the possibilities for the determination of neutral current vector and axial couplings to light quarks, and for constraining parameters in SMEFT analyses. Concerning top physics, we present the determination of $|V_{td}|$ and $|V_{ts}|$ and of anomalous couplings, including vector- and tensor $Wtb$ couplings, anomalous $t\bar{t} \gamma$ and $t\bar{t} Z$ couplings through, for example, magnetic and electric dipole moments, CP-odd top-Yukawa couplings, and FCNC $\gamma tq$ and $Z tq$ couplings.
[1] P. Agostini et al. (LHeC/FCC-he Study Group), J. Phys. G 48, 110501 (2021), arXiv:2007.14491 [hep-ex].
[2] F. Ahmadova et al., e-Print: 2503.17727 [hep-ex].
[3] The European Strategy for Particle Physics: 2026 Update - Recommendations by the European Strategy Group, https://cds.cern.ch/record/2950671/files/CERN-ESU-2025-002.pdf?version=1.

Speaker: Paul Newman

Bologna.submit.pdf

12:20 Impact of SIDIS measurements at future facilities towards the next generation of TMD analyses

We are moving toward a new generation of global analyses of unpolarized transverse-momentum–dependent distributions (TMDs) based on neural-network parameterizations, extending to SIDIS a framework previously tested using Drell–Yan data only.
At present, global fits with state-of-the-art perturbative accuracy and flavor dependence are available, although still based on traditional parameterizations. Building on these results, we study the impact of projected SIDIS measurements from future experiments such as SoLID at 12 GeV and the Electron–Ion Collider. We show that their extended kinematic coverage will be crucial to constrain regions of phase space that are currently poorly covered by existing data. In particular, we discuss the importance of precise cross-section measurements, rather than multiplicities, to fully exploit the potential of future facilities and to enable qualitatively new tests of TMD dynamics.

Speaker: Dr Matteo Cerutti (CEA Paris-Saclay)

Cerutti_DIS26.pdf

11:15 → 13:00 WG2 Small-x, diffraction and vector mesons

Convener: Michael Pitt (CERN)

11:15 Probing the transverse structure of nPDF modifications with jet production in ultra-peripheral Pb+Pb collisions with the ATLAS detector

In ultra-peripheral collisions (UPCs), emitted photons may participate in a hard-scattering process with partons within the struck nucleus, providing a clean, energetic probe of its parton distributions. This talk presents measurements of jet production in UPCs performed with the ATLAS detector using high-statistics 2018 Pb+Pb data. Events are selected using requirements on jet production, forward neutron emission, and rapidity gaps are then used to statistically separate inclusive photo-nuclear, photo-diffractive, and two-photon hard-scattering processes. The measured photo-nuclear cross-sections are compared to theoretical models in phase-space regions where significant nuclear PDF modifications are expected but not well constrained by world data, demonstrating the potential of these data to provide a strong new constraint on nuclear PDF effects. Additionally, measurements of jet production in UPCs where neither nucleus emits forward neutrons are performed. They may provide a novel method for probing the radial dependence of nuclear modifications within the target. Studies of jet production without forward neutron emission will also make possible the first measurement of diffractive jet photo-production in nuclear collisions, which will provide direct input for constraining existing models.

Speaker: Benjamin Gilbert (Lawrence Livermore National Laboratory)

Slides_DIS_bDepNPDF.pdf

11:35 Constraining gluon nPDFs with open heavy-flavor production in ultraperipheral heavy ion collisions with CMS

Open heavy-flavor production in ultraperipheral collisions (UPCs) enables the study of cold nuclear matter over a wide range of momentum transfers $Q$ and parton momentum fractions $x$, without significant final-state effects. In this talk we present the final results for the first measurement of $\mathrm{D}^0$ photoproduction in heavy-ion UPCs using data collected by the CMS experiment during 2023 PbPb collisions at the LHC. The measured production cross sections are shown as a function of the $\mathrm{D}^0$ transverse momentum, $2\lt p_{T}\lt12$ GeV/c and rapidity, $\eta \lt$ -2.

Speaker: Balasz Kovacs (MIT)

DIS_2026_Balazs_Kovacs_talk_final.pdf

11:55 Investigating nuclear shape via the Breit-Wheeler process in U+U UPCs at STAR

Dielectron production can occur in ultraperipheral heavy ion collisions (UPCs) via the Breit-Wheeler process, in which the quasi-real photons from the heavy ion-induced electromagnetic fields interact to produce a low transverse momentum dielectron pair. This production is sensitive to the charge radius and nuclear shape of the atomic nucleus sourcing the photons. By comparing the momentum dependence of the production cross sections in Au+Au and U+U to each other and to lowest-order quantum electrodynamics calculations, sensitivity to differences in nuclear shape and resulting field strength distributions can be studied. \par

We present experimental results for the dielectron production cross sections through the Breit-Wheeler process in U+U and Au+Au UPCs at $\sqrt{s_{NN}}$ = 193 and 200 GeV, respectively, at STAR at pair $p_{T} < 0.25$ GeV/c. We also present comparisons of these results with QED numerical calculations for the predicted cross sections, which allow new constraints on the charge radius and skin depth for the uranium nucleus.

Speaker: Mr Nicholas Jindal (The Ohio State University)

DIS2026_Jindal.pdf

12:15 Coherent and Incoherent $\phi$ Meson Photoproduction in Ultra-Peripheral Au+Au Collisions at $\sqrt{s_{NN}} = 200~\mathrm{GeV}$

Ultra-peripheral heavy-ion collisions provide a clean environment for studying photon--nucleus and photon--nucleon interactions. We present measurements of $\phi$-meson production in ultra-peripheral Au+Au collisions at $\sqrt{s_{NN}} = 200$~GeV with the STAR experiment at RHIC, performed via the $\phi \rightarrow K^{+}K^{-}$ decay channel. Those are the first RHIC studies of coherent and incoherent $\phi$-meson photoproduction. The two production mechanisms are separated using the transverse momentum of the reconstructed $\phi$ meson. Coherent production dominates at low $p_T$ and incoherent production at higher $p_T$ due to the different momentum-transfer scales of photon--nucleus and photon--nucleon interactions. The enhanced low-momentum tracking capability provided by the iTPC upgrade enables access to coherent $\phi$ production at STAR. Differential cross sections are extracted as functions of $p_T$, $p_T^2$, and rapidity for both production modes. The incoherent-to-coherent cross-section ratio is compared with predictions from STARlight and calculations based on the impulse approximation, providing sensitivity to possible suppression effects in photon--nucleus interactions. We also report results on azimuthal angular correlations, including $\cos(2\Delta\phi)$ modulations at higher transverse momentum.

Speaker: Xihe Han

DIS_final_xihe.pdf

12:35 Diffractive vector meson photo-production in oxygen-oxygen and neon-neon ultraperipheral collisions at energies available at the LHC

We present predictions for diffractive photoproduction of $\rho^0$ and $J/\psi$ vector mesons in ultra-peripheral oxygen–oxygen and neon–neon collisions using the energy-dependent hotspot model.
A striking prediction of this model is that the energy dependence of the incoherent cross section provides a clear signature of saturation effects: the cross section rises with energy, reaches a maximum, and decreases as saturation sets in. The position of this maximum depends on the mass of the produced vector meson and the mass number of the target. In our previous work, we demonstrated that there is a dependence on the Mandelstam-$t$ variable, with the maximum appearing at $|t|$ values corresponding to the size of subnucleonic hotspots. This model has been successfully compared to LHC data for coherent and incoherent $J/\psi$ production in Pb–Pb UPCs.
We extend this approach to a detailed study of photoproduction of $\rho^0$ and $J/\psi$ in O–O and Ne–Ne collisions, considering also two different nuclear shape models for each system: a traditional Woods–Saxon parameterization, and an alpha-cluster model for oxygen and a bowling-pin–like shape for neon. These measurements are experimentally feasible with data collected during the 2025 LHC runs.

These studies have been submitted for publication and posted in arxiv:2509.11359 [hep-ph].

Speaker: Mrs Alexandra Ridzikova (Czech Technical University in Prague)

Ridzikova_DIS2026.pdf

11:15 → 13:00 WG4 QCD with Heavy flavours and Hadronic Final States

11:15 State of the art event generation for the EIC and future DIS experiments

I this talk we will discuss state-of-the-art hadron-level predictions for the deep-inelastic scattering process at next-to-leading-order precision for several multiplicities, consistently merged in one sample, based on [1]. For the first time at this level of accuracy, we consider both neutral and charged current deep-inelastic scattering at the upcoming Electron-Ion Collider and present the first application of consistent next-to-leading-order merging to charged current deep-inelastic scattering in general. We will discuss precision phenomenology focused on traditional DIS observables and
hadronic event shapes, including 1-jettiness, jet multiplicities, and leading-jet transverse momentum.

[1] Phys.Rev.D 112 (2025) 7, 074039.

Speaker: Daniel Reichelt

DIS_2026_DReichelt.pdf

11:35 NNLO precise predictions for hadron-in-jet observables in e+e- collision

The production of identified hadrons in jets in e+e− scattering allows for detailed analyses of fragmentation functions in a clean environment. We present our novel calculation of next-to-next-to leading order (NNLO) corrections to hadron-in-jets observables for the e+e− → 2j and e+e− → 3j processes. In particular, we study the impact of the choice of different fragmentation scales in our predictions to the comparison with experimental data.

Speaker: Francesco Merlotti (ETH Zürich)

merlottiDIS26.pdf

11:55 Precision Simulation of Photoproduction and Diffractive Jets for the EIC and HERA

Photoproduction and diffraction are complementary to the DIS regime usually considered at $ep$ colliders. They contribute significantly to the hadronic final-state at experiments like HERA and the upcoming EIC and are hence of vital interest for, e.g., jet studies in these setups.

In this talk I will present recent calculations of jet production in the photoproduction and diffractive channels. For the first time, NLO QCD accuracy matched to parton showers is reached for these regions. In the photoproduction regime, we quantify the sensitivity of EIC jet measurements to the currently poorly constrained parton-in-photon PDFs, demonstrating the collider's potential to resolve the photon's hadronic structure. For diffraction, we compare against data form ZEUS and H1 and study the impact of future EIC data.

Speaker: Peter Meinzinger (Universität Zürich)

Meinzinger_DIS2026.pdf

12:15 Diphoton production with realistic photon isolation

Photon pair production is a key benchmark process at the LHC, relevant for Higgs measurements and searches for new physics. Photons are experimentally identified using isolation criteria that allow limited hadronic energy in a cone around the photon, admitting contributions from collinear radiation and parton-to-photon fragmentation. We compute NNLO QCD corrections to diphoton production including these effects, enabling a faithful implementation of experimental isolation prescriptions.

Speaker: Giovanni Stagnitto (Istituto Nazionale di Fisica Nucleare)

GGfrag_DIS26.pdf

12:35 QCD physics in e+e- collisions below the Z peak at FCC-ee

Measurements of hadronic final states in $e^{+}e^{-}$ collisions at centre-of-mass (CM) energies below the Z peak can notably extend the FCC-ee physics reach in terms of precision quantum chromodynamics (QCD) studies. Hadronic final states can be studied over a range of hadronic energies $\sqrt{s_\mathrm{had}} \approx 20\mbox{--}80\,\mathrm{GeV}$ by exploiting events with hard initial- and final-state QED radiation (ISR/FSR) during the high-luminosity Z-pole run, as well as in dedicated short (about one month long) $e^{+}e^{-}$ runs at CM energies $\sqrt{s} \approx 40\,\mathrm{GeV}$ and $60\,\mathrm{GeV}$. Using realistic estimates and fast detector simulations, we show that data samples of about $10^{9}$ hadronic events can be collected at the FCC-ee at each of the low-CM-energy points. Such datasets can be exploited in a variety of precision QCD measurements, including studies of light-, heavy-quark and gluon jet properties, hadronic event shapes, fragmentation functions, and nonperturbative dynamics. This will offer valuable insights into strong interaction physics, complementing data from nominal FCC-ee runs at higher center-of-mass energies, $\sqrt{s} \approx 91, 160, 240,$ and $365\,\mathrm{GeV}$.

Speaker: Andrii Verbytskyi (MPP)

DIS2026-AndriiVerbytskyi.pdf

11:15 → 13:00 WG5 Spin and 3D-structure

Convener: Tyler Kutz (Johannes Gutenberg University Mainz)

11:15 Exclusive electroproduction of dijets

In this talk, we introduce our recent work on the exclusive electroproduction of dijets. This process, only tentatively studied in the past, provides a novel way to probe generalized parton distributions (GPDs), and it may be within the reach of future colliders. We obtain the complete set of amplitude expressions at leading order (LO), allowing us to construct observables that are sensitive to different types of GPDs. The predictions for experiments at the future Electron-Ion Collider (EIC) are made using the PARTONS software. We also systematically study the effect of hadronization with the Lund model. At LO, we find terms that provide interesting opportunities to probe quark GPDs at $x \neq \xi$, we analyze their experimental sensitivity in different kinematic regions.

Speaker: ZHUOYI PANG (National Centre for Nuclear Research, Warsaw)

dijet.pdf

11:35 Deeply virtual neutral pion electroproduction

Deeply virtual electroproduction of neutral pions has emerged as an important experimental channel for exploring the proton’s structure through deeply virtual exclusive reactions. In this talk, I will present new measurements of deeply virtual π^0 electroproduction based on a comprehensive analysis of data covering a wide kinematic range in Q2 and Bjorken x that are accessible at the CLAS12 experiment at Jefferson Laboratory. The results are obtained from high-statistics data in the valence-quark region and include detailed measurements of exclusive cross sections and their kinematic dependences. The broad phase-space coverage enables systematic studies across kinematic variables and provides a consistent experimental benchmark for deeper understanding of nucleon structure.
These measurements significantly extend existing experimental knowledge of neutral pion electroproduction and demonstrate the capabilities of modern exclusive measurements over a wide kinematic domain.

Speaker: Igor Korover (Tel Aviv University)

DIS2026_igor.pdf

11:55 Measurement of the hard exclusive neutral pion muoproduction cross section at COMPASS

Hard Exclusive Meson Production is a very promising reaction to access Generalized Parton Distributions. Measurement of the cross section for hard exclusive neutral pion muoproduction on the proton was performed at COMPASS in 2016 at the M2 beamline of the CERN SPS using 160 GeV/c longitudinally polarised positive and negative muon beams scattering off a 2.5 m long liquid hydrogen target. Results were obtained in a wide kinematic region with the photon virtuality Q2 up to 8 (GeV/c)$^2$ and the Bjorken variable xBj ranging from 0.016 to 0.45. We will report on the virtual-photon proton cross section averaged over the µ+ and µ- cross sections and on its dependence on the squared four-momentum transfer between initial and final proton in the range 0.08 (GeV/c)$^2$ < |t|< 0.64 (GeV/c)$^2$ and on the azimuthal angle between the scattering plane and the π0 production plane. Fitting the azimuthal dependence yields the sum of the contributions by transversely and longitudinally polarised photons as well as transverse-transverse and longitudinal-transverse interference contributions. They are studied as functions of four-momentum transfer, photon virtuality and virtual-photon energy. The COMPASS results provide input to constrain Generalized Parton Distributions, in particular chiral-odd (“transversity”) ones.

Speaker: Po-Ju Lin (National Central University)

2026_DIS_COMPASS_pi0_pjlin.pdf

12:15 Measurement of Deeply Virtual Compton Scattering with the Neutral Particle Spectrometer in Hall C at JLab

The internal structure of nucleons remains a central challenge in hadronic physics, particularly in understanding how quarks and gluons contribute to their mass and spin. Introduced in the 1990s, the generalized parton distributions (GPDs) play a crucial role in providing multiple pieces of information to reveal these mysteries. Experimentally, GPDs can be accessed through the Compton Form Factors (CFFs), and the simplest process to probe them is Deeply Virtual Compton Scattering (DVCS).

The latest experiment in the Hall A/C GPD programs at Jefferson Lab (JLab) was performed from 2023 to 2024 using the newly installed Neutral Particle Spectrometer (NPS) in Hall C. The NPS calorimeter, constructed using 1080 lead tungstate (PbWO$_4$) crystals, offers high energy resolution for detecting photons emitted in DVCS processes, thereby playing a key role in measuring DVCS cross sections. In this talk, I will present our experimental setup and the status of data analysis.

Speaker: Hao Huang (IJCLab, CNRS-IN2P3)

DVCS_NPS_HallC_JLab_DIS2026_v4.pdf

12:35 DVCS Cross Section Measurements at COMPASS

Preliminary COMPASS results on the Deeply Virtual Compton Scattering (DVCS) cross section will be presented. They have been obtained from exclusive single-photon production by scattering the 160 GeV muon beams of the SPS M2 beamline off a 2.5 m long liquid hydrogen target. The recoil proton was measured in a barrel-shaped time-of-flight detector surrounding the target. The scattered muons were detected by the COMPASS spectrometer and the photons by electromagnetic calorimeters including a new large-angle calorimeter. We will show the charge-spin average DVCS cross section differential as a function of the squared four-momentum transfer to the proton. This cross section is expected to be sensitive to the transverse extension of partons in the proton. COMPASS allows the first access to the Bjorken-x domain of sea quarks.

Speaker: Gursimran Kainth (University of Connecticut)

DIS2026_Kainth.pdf

12:45 Spin Density Matrix Elements in Exclusive Muoproduction of $\phi$ Mesons at COMPASS

Preliminary results on Spin Density Matrix Elements in hard exclusive muoproduction of $\phi$ mesons on the proton are presented. The measurements were performed at COMPASS using 160 GeV/c polarised positive and negative muon beams incident impinging on a liquid hydrogen target. The covered kinematic range is $5 < W < 17~\mathrm{GeV}$, $1.0 < Q^2 < 10.0~\mathrm{GeV}^2$, and $0.01 < p_T^2 < 0.5~\mathrm{GeV}^2$. Here, $Q^2$ denotes the virtuality of the exchanged photon, $W$ the invariant mass of the final-state hadronic system, and $p_T$ the transverse momentum of the $\phi$ meson with respect to the virtual-photon direction.

The extracted Spin Density Matrix Elements allow the study of helicity transitions in exclusive $\phi$ production, in particular transitions from transversely polarised virtual photons to longitudinally polarised vector mesons, which provide a test of s-channel helicity conservation. Contributions from natural-parity-exchange and unnatural-parity-exchange amplitudes are investigated as functions of $W$, $Q^2$, $p_T$, and $x_B$.
These results provide constraints for phenomenological models based on Generalised Parton Distributions (GPDs) and may allow a model-dependent assessment of the role of parton-helicity-flip (transversity) GPDs in exclusive $\phi$ meson production.

Speaker: Kamil Augsten (Czech Technical University in Prague)

KAugsten_Phi_SDMEs_DIS26_v2.pdf

13:00 → 14:30 Lunch break

14:30 → 16:15 WG1 Structure functions and parton densities

Convener: Markus Diehl (Deusches Elektronen-Synchrotron DESY)

14:30 The Pion Parton Distribution Puzzle in High x Region

We discuss recent extraction of parton distribution function of pion in the valence region
which observed an unexpectedly soft $(1-x)^\beta$, $\beta\sim 1$ behavior, contradicting several theoretical predictions including the ones based on the hard
gluon exchange, according to which $\beta =2$. In this work we calculated the pion PDF within the theoretical approach based on spectral
function representation of valence structure in hadrons.
The approach was first applied for nucleon valence PDF’s which demonstrated the existence of pion-cloud structure in the nucleon already at the starting $Q_0$ for which initial PDF’s are defined. Our calculation also shows substantial high momentum component in nucleon for large x. One of the non-trivial predictions of spectral function approach is that the position of the peak for x weighted nucleon valence PDF (xPDF) has an upper bound of 1/4 (instead of 1/3 as expected in simple parton models) and confirmed experimentally.
Applying the same approach for calculation of pion valence PDF’s, we first observe that no additional residual structure exists in the pion as it was the case for nucleons. Our calculation largely describes the recently obtained phenomenological PDF’s by JAM collaboration.
We observe that the Feynman mechanism is responsible for pion PDF at
relatively large x leaving little room for the hard q\bar q interaction at large x region.One non-trivial observation is that the peak position of xPDF defines the analytic behavior of valence PDF at $x\to 1$ limit.

Speaker: Misak Sargsian (Florida International University)

DIS2026ms.pdf

DIS2026ms.pptx

14:50 Meson Structure Study via Drell-Yan Production at AMBER Experiment

Understanding meson structure through parton distribution functions (PDFs) remains a fundamental challenge in QCD. Existing pion PDF measurements rely on sparse, decades-old data from heavy nuclear targets, while kaon structure is constrained by only a few hundred events. Valence quark distributions have minimal experimental guidance, and sea quark and gluon content remain essentially unmeasured.

The AMBER experiment at CERN will address these limitations through high-statistics Drell-Yan measurements using 190 GeV hadron beams on light targets. The Drell-Yan program, approved as part of AMBER Phase-I (2023-2031), will conduct production running starting in 2029 following Long Shutdown 3, with approximately 280 days of data collection planned over two years.

Drell-Yan dimuon production directly probes quark distributions, while J/psi and psi' charmonium production provides complementary access to gluon PDFs. J/psi polarization measurements further constrain production mechanisms by distinguishing quark-antiquark annihilation from gluon fusion processes. The natural kaon component in the hadron beam enables simultaneous kaon structure measurements that will exceed existing datasets by an order of magnitude. AMBER will deliver the world's largest pion-induced Drell-Yan and charmonium sample within this decade, providing essential constraints for global PDF analyses and establishing benchmarks complementary to future Electron-Ion Collider measurements.

Speaker: Zoë Earnshaw

DIS2026-AMBER-DY.pdf

15:10 JAM global QCD analysis of pion and kaon PDFs

We review recent results from the JAM Collaboration on pion and kaon PDFs obtained from global QCD analysis of experimental Drell-Yan and leading neutron electroproduction data, together with lattice QCD calculations of PDF moments and Ioffe time distributions. The analysis indicates a softer valence up-quark distribution in the $K^+$ compared with the $\pi^+$, and provides the first empirical evidence for significantly different valence up and anti-strange densities in the kaon. Inclusion of recent lattice calculations of gluonic pseudo Ioffe-time distributions also significantly reduces uncertainties on the gluon PDF, revealing a higher gluon density in the pion at large momentum fractions than in the proton.

Speaker: Dr Wally Melnitchouk (Jefferson Lab)

Melnitchouk - new.pdf

15:30 New parton distributions of the real photon

Precise determination of the partonic structure of real photons has attracted renewed interest in view of ongoing studies of high-energy photon-induced processes in ultraperipheral collisions (UPCs) at the Large Hadron Collider (LHC) and at the future Electron-Ion Collider (EIC). Despite being fundamental in their own right and essential for QCD phenomenology of hard processes initiated by resolved photons, the quark and gluon distributions of the photon are poorly known and merit a new analysis employing modern tools of statistical data analysis.

We determine new sets of leading order (LO) and next-to-leading order (NLO) parton distributions (PDFs) of the real photon by performing a global QCD analysis of the world data on the photon structure function $F_2^{\gamma}(x,Q^2)$ measured in deep-inelastic scattering (DIS) processes on a real photon target in electron-positron collisions. Our analysis improves on the results available in the literature by providing uncertainties in the form of Monte-Carlo replicas and PDFs in the LHAPDF6 format. While electron-positron data determines the singlet quark distribution very well at both LO and NLO, the gluon distribution is constrained to a much lesser degree, especially at LO. For this analysis, we have developed an open-source framework, which extends the pineline framework to the photon case and includes the program solving the inhomogeneous $Q^2$ evolution of photon PDFs, $\gamma$EKO.

Speaker: Madhav Chithirasreemadam (University of Jyväskylä)

Madhav_DIS_2026.pdf

15:50 Open charm photoproduction with G$\gamma$A-FONLL at LHC and EIC

Open charm and beauty production in photonuclear collisions offer a theoretically controlled way to study the dynamics of quarks and gluons in nuclei. In this talk, we present the first next-to-leading order predictions for the inclusive production of charmed mesons in ultraperipheral lead–lead collisions at the LHC, obtained with the new G$\gamma$A–FONLL framework. The framework relies on FONLL (Fixed-Order Next-to-Leading Logarithm) to model heavy-quark production in photonuclear collisions and employs a photon-flux reweighting procedure to describe production cross sections in ultraperipheral heavy-ion collisions. Recent calculations of the production cross section of $D^0$ mesons in ultraperipheral Pb–Pb collisions (Xn0n) at the LHC are presented and compared with the first experimental results. The predictions are benchmarked against different choices of nuclear parton distribution functions, fragmentation functions, and renormalization and factorization scales. New predictions for the cross section of diffractive open charm production in UPCs, as well as for open charm photoproduction at the Electron–Ion Collider, obtained with the same framework, will also be presented.

Speaker: Anna Stasto (Penn State University)

AnnaStasto_D0_UPC.pdf

14:30 → 16:00 WG2 Small-x, diffraction and vector mesons

Convener: Cristovao Fernandes Vilela

14:30 The fragmentation mechanism in diquarkonia production

Quarkonium-pair production is a rich observable, providing valuable insights into gluon TMDs, double parton scattering, and, of course, the production mechanism itself. While direct production has been frequently studied, here we investigate the contribution from heavy-quark fragmentation, including, in particular, $D_{Q\to H_1 H_2}$ for the fragmentation of a heavy quark into two quarkonia.

Our analysis is performed within the color glass condensate effective theory, and we present our results for double $J/\psi$ production.

Speaker: Benjamin Guiot (Universidad federico santa maria)

DIS2026.pdf

14:50 Saturation Onset and Centrality Dependence for Heavy Mesons

Perturbative Quantum Chromodynamics describes the strong interaction among quarks and gluons. Specifically, the gluons are supposed to recombine at low momentum (low x) for extreme conditions, onseting saturation to restore unitarity. This challenging phenomenon is faced experimentally with peripheral and ultraperipheral production of heavy mesons, J/Psis and Upsilons, mostly gluons dependent. The modelling for photoproduction considering different event geometries, at distinct classes of centrality, for cross sections distributions on energy, transverse momentum, rapidity are presented, compared with data with good agreement for pp, pA, and AA. Simulations for FoCal (ALICE) and its capabilities to distinguish each heavy meson for new kinematical limits are also shown.

Speaker: Prof. M.Beatriz Gay Ducati (UFRGS)

DIS2026_MBGD.pdf

15:10 Complete NLO BFKL impact factors for quarkonium hadroproduction in NRQCD: the case of ${}^1 S_0^{[1]}$, ${}^1S_0^{[8]}$, and ${}^3S_1^{[8]}$ states

Based on: https://arxiv.org/abs/2601.04142

We present the first complete next-to-leading-order calculation of the impact factors for hadroproduction of the ${}^1S_0^{[1]}$, ${}^1S_0^{[8]}$, and ${}^3S_1^{[8]}$ NRQCD states
within the BFKL formalism. We complete the recent virtual-correction computation presented in \href{https://doi.org/10.1007/JHEP12(2024)129}{JHEP 12 (2024) 129} by that of the real-emission contributions. We observe the cancellation of the soft divergences between these real- and virtual-emission contributions and we note that the surviving collinear singularities are compatible with factorisation up to one loop for a novel class of processes where BFKL resummation can be applied. Our work indeed represents the first complete NLO quarkonium impact factor in the BFKL framework and paves the way to first next-to-leading-logarithmic-precision studies for hadroproduction of forward-backward quarkonium associated production at hadron colliders.

Speaker: Michael Fucilla

Fucilla.pdf

15:30 Unified Resummation of Soft Gluon Radiation in Heavy Meson Pair Photoproduction

We develop a unified resummation framework for heavy-meson pair photoproduction that treats soft-gluon radiation in a massive scheme for $|q| \lesssim m_Q$ and is consistent with the massless limit $m_Q \ll |q|$, where $q$ denotes the transverse momentum of the pair and $m_Q$ the quark mass. This framework describes the full correlation regime $|q| \ll |P|$, with $P$ the pair's relative transverse momentum. Next, within the Color Glass Condensate framework, we quantify the impact of soft gluon radiation on two important phenomenological observables, namely, the azimuthal $\Delta\phi$ correlation and the harmonic asymmetries $\langle \cos(2n\phi_{qP})\rangle$. Our results show that the resummation provides an excellent description of the H1 $\Delta\phi$ data. We then find that the angular-asymmetry harmonics are sizable and their ratios in $\gamma A$ to $\gamma p$ collisions are highly sensitive to gluon saturation. We further find a clear mass hierarchy in both observables, indicating that heavy-quark masses suppress soft radiation and thereby enhance genuine small-$x$ saturation signals. Our work demonstrates that heavy-quark pair photoproduction provides a quantitative probe of gluon saturation, directly measurable in forthcoming EIC and UPC measurements. Finally, the unified resummation is readily extendable to other processes involving massive particles and jets in both $eA$ and $pA$ collisions.

Speaker: Dr Yu Shi (Ecole Polytechnique, CNRS)

SY_DIS2026.pdf

14:30 → 16:15 WG3 Electro-weak physics/higgs/top and BSM: Multiboson

Conveners: Ken Mimasu (University of Southampton), Menglin Xu

14:30 Recent developments in vector boson polarization modelling in Sherpa (17‘+3’)

Probing the electroweak sector and electroweak symmetry breaking in unprecedented detail is one of the primary goals of the upcoming HL-LHC program. Measurements of vector-boson polarizations represent a promising avenue toward this objective. The extraction of the different polarization components from experimentally accessible unpolarized distributions requires accurate particle-level polarization templates derived from Monte Carlo simulations.

Despite recent progress in the Powheg and Sherpa event generators, enabling full or approximate NLO QCD+PS calculations, a complete NLO QCD + NLO EW + PS description for arbitrary processes has not yet been achieved. In this talk, I will discuss ongoing developments in the Sherpa event generator toward automated fixed-order polarization predictions at NLO QCD + NLO EW - an essential step towards achieving this goal. In addition to these efforts, I will present the recent extension of Sherpa allowing for the modeling of polarized loop-induced processes at fixed leading order and matched to the parton shower, as well as report on the current status of an amplitude-assisted polarization tagger based on Sherpa predictions.

Speaker: Mareen Hoppe

Recent developments of vector boson polarization modelling with SHERA-1.pdf

14:50 Multiboson measurements with the ATLAS detector (17'+3')

This talk will present the latest measurement results from the ATLAS experiment, concerning production or interactions among multiple vector bosons, including production of ZZ, Wgamma dibosons, vector boson fusion production of W bosons, and production of ZZgamma tribosons. These latest results offer a next-level investigation into the SM electroweak sector.

Speaker: Alain Bellerive

ABellerive_ATLAS_DIS2026.pdf

15:10 Multiboson production and vector boson scattering in CMS (20'+5')

Multiboson production at the LHC turns the CMS detector into a stress‑tester of the Standard Model, where intertwined gauge bosons expose the full richness of the electroweak force. Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the standard model, since it involves both self-couplings of vector bosons and coupling with the Higgs boson. This talk presents the latest results on diboson and triboson production in proton–proton collisions in multiple final states and topologies that push the experiment into previously unexplored territory, and the latest measurements of production cross sections of vector boson pairs in association with two jets in proton-proton collisions at the LHC are reported using a data set recorded by the CMS detector.

Speaker: Tianyu Mu (Peking University (CN))

DIS_Tianyu.pdf

15:35 Planar three-loop four-point master integrals with two off-shell legs (17'+3')

We present the computation of all planar three-loop four-point integral families with two off-shell legs, which are relevant for the leading-colour N3LO QCD corrections to the production of two massive vector bosons at hadron colliders. We employ the method of differential equations, enhanced by the construction of pure bases for the master integrals of each family, and utilize finite field techniques for the reconstruction of the connection matrices. To evaluate the differential equations, we use the method of generalized power-series expansions, as implemented in the public packages DiffExp and Amflow, with our implementation allowing for numerical evaluation at any phase-space point in the physical region. Compared to the two-loop case, the problem is significantly more involved, not only due to the larger number of master integrals, but also because of the appearance of new square roots and an extended symbol alphabet.

Speaker: Dhimiter Canko (University of Bologna and INFN)

VV_DIS_2026.pdf

15:55 Charting the spin structure of WZ pairs at the LHC (17'+3')

The study of quantum-information observables at the TeV energy scale has intensified the focus on precision measurements of the spin structure of weak-boson pairs at the LHC. We show that a robust spin interpretation of diboson events demands an accurate determination of joint polarisation fractions and of the off-diagonal entries of the spin-density matrix. This requires the inclusion of electroweak and QCD higher-order corrections, as well as parton-shower effects, both in and beyond the Standard Model. We summarise recent progress in the calculation of spin correlations for inclusive WZ production, including NNLO QCD + NLO EW predictions in the Standard Model (2510.25898) and NLO QCD predictions in the Standard Model Effective Field Theory (2507.21768, 2601.09540). All results are presented in realistic kinematic setups relevant for the interpretation of LHC Run-2 and Run-3 data.

Speaker: Giovanni Pelliccioli (University of Milano-Bicocca)

gp_dis_26.pdf

14:30 → 16:10 WG4 QCD with Heavy flavours and Hadronic Final States

14:30 How well does NRQCD describe quarkonium production data?

The question how well nonrelativistic QCD (NRQCD) factorization can describe quarkonium production has been subject to debate since its invention. We review our recent reanalysis of a classic next-to-leading order color octet (CO) long distance matrix element (LDME) fit to large transverse momentum $p_T$ $J/\psi$ and $\eta_c$ LHC production data. Our analysis differs from previous analyses of this kind not only by implementing for the first time a systematic treatment of scale uncertainties, but also by scrutinizing a much broader range of observables. Surprisingly, $J/\psi$ hadroproduction is well described up to the highest measured values of $p_T$. Potential NRQCD based relations nontrivially lead to a perfect description of $\Upsilon(nS)$ production data. Furthermore, $J/\psi$ production in $\gamma p$ and $\gamma \gamma$ collisions is, contrary to prevailing conceptions, reproduced down to $p_T=1$ GeV, as long as the region of large inelasticity $z$ is excluded. The overall picture is much rosier than usually perceived, the more so as the remaining discrepancies appear in phase space regions where solutions via varying kinds of resummations have been proposed.

Speaker: Dr Mathias Butenschoen (University of Hamburg)

Butenschoen_DIS2026.pdf

14:50 Bound-state production in MadGraph5_aMC@NLO

In this talk, I present the first implementation in MadGraph5_aMC@NLO for bound-state production, including quarkonium, leptonium, and $B_c$ mesons within Non-Relativistic QCD and Non-Relativistic QED. I focus on the extension of MadGraph5_aMC@NLO to quarkonium states, the simplest bound states in QCD, and describe the capabilities of the new framework for inclusive and associated S-wave quarkonium production in a wide variety of experimental environments at Leading Order (LO). I present a comprehensive benchmarking of the LO implementation in MadGraph5_aMC@NLO against Helac-Onia, demonstrating excellent agreement and validating the approach. I further illustrate the expanded functionality of the tool, enabling phenomenological studies that complement and extend the current state of the art. These developments provide the community with a unified, automated, and efficient framework for bound-state production in QED and QCD, and establish a solid foundation for our future next-to-leading-order extensions.

Speaker: Alice Colpani Serri (Warsaw University of Technology (WUT))

ACS_MG5-talk_DIS26.pdf

15:10 Collinear fragmentation of pseudoscalar quarkonia from NLO NRQCD

We investigate the inclusive hadroproduction of pseudoscalar heavy quarkonia, $\eta_c$ and $\eta_b$ mesons, in high-energy proton collisions at the 13 TeV LHC, focusing on the moderate to large transverse momentum regime. Our theoretical framework is based on the single-parton collinear fragmentation mechanism within a variable-flavor number scheme and it builds on Non-Relativistic QCD (NRQCD), which describes the formation of the heavy quark bound state at the initial scale at NLO. To accurately describe this process, we make use of the symJETHAD symbolic engine to produce and publicly release a new set of collinear fragmentation functions, denoted NRFF1.0. We performed our analysis within the NLL/NLO$^{+}$ hybrid factorization framework which has been used to study high-precision theoretical predictions for high-energy observables sensitive to quarkonium final states at the 13 TeV LHC. These FFs consistently include all partonic channels and evolve via standard DGLAP equations, accounting for all partonic thresholds. This framework offers a direct path toward addressing the long-standing quarkonium production puzzle and can be extended to investigate quarkonium fragmentation within jet. Furthermore, we extend our fragmentation analysis to the physics of dense media investigation of heavy-flavor fragmentation function evolution in the hot Quark-Gluon Plasma.

Speaker: Francesca Lonigro

DIS2026__.pdf

15:30 Factorizing quarkonium production matrix elements using effective field theory

We use effective field theory to factorize production matrix elements that appear in the NRQCD framework for quarkonium cross sections. By applying a Hubbard–Stratonovich transformation and appropriate field redefinitions, we show that the soft and ultrasoft sectors of NRQCD can be decoupled from the heavy quark and antiquark fields in a hybrid vNRQCD/pNRQCD Lagrangian at leading order in the velocity power-counting. This enables us to re-factorize quarkonium production matrix elements in terms of matrix elements of color-singlet composite fields, which we can write as the wave-function at the origin, and state independent vacuum correlators of chromo-electric and chromo-magnetic gluon fields. This approach verifies powerful relationships between the LDMEs of different S-wave quarkonia originally derived using pNRQCD. Additionally, it allows us to derive new relationships for the production matrix elements used in the transverse momentum dependent factorization (TMD) framework, known as TMD soft transition functions, providing a much stronger set of constraints on these nonperturbative operators. This work significantly advances our understanding of quarkonium production, particularly at small transverse momentum, and should pave the way to address longstanding tensions between theory and experiment on quarkonium production cross sections at small $p_T$.

Speaker: Marston Copeland (Los Alamos National Laboratory)

DIS presentation Copeland.pdf

14:30 → 16:00 WG5 Spin and 3D-structure

Convener: Matteo Cerutti

14:30 Learning GPDs from Lattice QCD

Generalized parton distributions (GPDs) provide a unified description of the three-dimensional structure of hadrons, encoding both spatial and momentum information. Their determination, however, remains a challenging inverse problem due to limited experimental constraints and theoretical complexities in their extraction. Recent advances in lattice QCD (LQCD) have made it possible to access the Bjorken-$x$ dependence of hadron structure, moving beyond the traditional restriction to a few low moments.
In this talk, we present the extraction of GPDs via machine-learning frameworks from LQCD calculations performed at physical pion mass.

Speaker: Huey-Wen Lin (Michigan State University)

Learning GPD from LQCD

14:50 Neural Network Representation of Generalized Parton Distributions (NNGPD)

I will present a neural-network–based framework for modeling generalized parton distributions, referred to as NNGPD, in which GPDs are represented as flexible functions constrained through physically motivated integral relations. This approach reflects the inverse-problem character of GPD phenomenology - without assuming a specific functional ansatz - where experimental and theoretical information is incorporated into the training procedure via loss functions enforcing convolution integrals (Compton form factors), as well as Mellin moments accessible in lattice QCD. We find that the neural-network representation reproduces the main features of the GPDs over the relevant kinematic domain, despite being constrained only by their integral projections thus demonstrating its viability for constraining GPDs through global physical observables. A thorough analysis of both epistemic and statistical uncertainty, the latter being inherent to the sampling of allowed GPD solutions, will be discussed. Our approach provides a basis for future phenomenological applications incorporating experimental measurements, including those anticipated at the Electron–Ion Collider.

Speaker: Simonetta Liuti (University of Virginia)

NNGPD_DIS26.pdf

15:10 The Proton Energy Correlator

We introduce the spin-dependent proton energy correlator in both the current and target fragmentation regions. We also present a new result for the NNLO helicity DGLAP splitting function, finding a small discrepancy with existing results in the literature.

Speaker: Yu Jiao Zhu (Max-Planck Institute for Physics)

dis2026_zhu.pdf

15:30 Pion and nucleon relativistic angular momentum and boost distribution

We present a detailed investigation of the relativistic spatial structure of transverse angular momentum, including both orbital and intrinsic spin, and examine how these quantities are modified by boost effects. Using the quantum phase-space (Wigner) formalism, we begin with three-dimensional spatial distributions of transverse orbital angular momentum, intrinsic spin, and boost in an arbitrary Lorentz frame. By integrating these 3D distributions along the longitudinal direction, we obtain, for the first time, the corresponding 2D spatial distributions of orbital angular momentum, intrinsic spin, total angular momentum, and boost for both spin-0 and spin-1/2 systems. These distributions are analyzed with respect to three physically relevant pivots: the center of mass, the center of energy, and the center of spin. We verify the transverse spin sum rule for all three pivots for spin-1/2 targets. Interestingly, we find that both the transverse total angular momentum and the boost distribution exhibit non-trivial structure even for spin-0 systems, highlighting the dynamical richness of relativistic effects. We further show how the spatial patterns of transverse orbital angular momentum, intrinsic spin, and total angular momentum vary with the target’s momentum. Finally, we also provide the corresponding distributions in the light-front Drell–Yan frame, establishing a clear connection between instant-form and light-front descriptions of transverse angular momentum and boost.

Speaker: Ravi Singh (Indian Institute of Technology Bombay)

DISravi.pdf

14:30 → 16:15 WG6 Current upgrades and future experiments

Convener: Boxing Gou (Institute of Modern Physics, CAS)

14:30 Opportunities for Imaging Light Nuclei with a Second Interaction Region at the Electron-Ion Collider

The upcoming Electron-Ion Collider (EIC) will address several outstanding puzzles in modern nuclear physics. Key questions—such as the partonic structure of nucleons and nuclei and the origin of their mass and spin—can be explored through high-energy electron–proton and electron–nucleus collisions. To maximize its scientific reach, the EIC community has advocated for the addition of a second interaction region equipped with a detector complementary to the EIC general purpose collider detector, ePIC. The pre-conceptual design of this interaction region aims to provide a different configuration from the first interaction region, which enhances forward acceptance at very small scattering angles ($\theta \sim 0$ mrad). This machine configuration would significantly benefit exclusive, tagging, and diffractive physics programs, complementing those of the ePIC experiment. In particular, accessing coherent diffractive processes on light nuclei by tagging of the full, intact nucleus is essential for mapping their spatial parton distributions. In this walk, we present a systematic study of the detection capabilities for light nuclei at a second EIC interaction region, with a detailed discussion of the accessible kinematic phase space and its implications for imaging. The results will provide significant insight into the detector proposal and future improvements of IR-8 at the EIC.

Speaker: Wan Chang (Nanyang Normal University)

DIS2026_WanChang.pdf

14:50 Forward Particle Identification at the EIC with the ePIC dRICH Detector

The dual-radiator Ring Imaging Cherenkov detector (dRICH) is a key component of the particle identification (PID) system of the ePIC experiment at the future Electron-Ion Collider (EIC). The detector is designed to provide efficient separation of charged hadrons over a broad momentum range in the forward (1.5 < $\eta$ < 3.5) hadron-going region, enabling precision studies of nucleon and nuclear structure through semi-inclusive and exclusive processes.

The dRICH concept employs a combination of gaseous and aerogel radiators to extend the PID coverage from $\sim$ 3 GeV/c up to about $\sim$ 50 GeV/c, coupled to a focusing optical system that images Cherenkov photons onto a finely segmented photon-detection plane. The detector will employ silicon photomultipliers (SiPMs) as photon sensors, providing single-photon sensitivity, excellent timing performance, and immunity to the strong and nonuniform magnetic field at the dRICH location ($\sim$ 1 T), with a total of more than 300000 readout channels covering $\sim$ 3 m$^{2}$. Their use constitutes a key technological innovation, representing the first application of SiPMs for large-area single-photon detection in a high-energy physics experiment. However, their limited radiation hardness requires careful qualification and mitigation strategies to preserve single-photon sensitivity over the lifetime of the ePIC experiment.

In this talk, we will present highlights of the past and ongoing R&D and engineering activities for the key components of the detector, with some emphasis on the photosensor system, together with simulation results demonstrating the expected performance of the dRICH in the ePIC experimental environment. These studies indicate that the detector meets the stringent particle-identification requirements of the EIC physics programme and validate the adopted detector concept.

Speaker: Simone Vallarino (Istituto Nazionale di Fisica Nucleare)

ePIC_dRICH_DIS2026_Vallarino.pdf

15:10 Overview of ATLAS forward proton detectors: status, performance and new physics results

A key focus of the physics program at the LHC is the study of head-on proton-proton collisions. However, an important class of physics can be studied for cases where the protons narrowly miss one another and remain intact. In such cases, the electromagnetic fields surrounding the protons can interact producing high-energy photon-photon collisions. Alternatively, interactions mediated by the strong force can also result in intact forward scattered protons, providing probes of quantum chromodynamics (QCD). In order to aid identification and provide unique information about these rare interactions, instrumentation to detect and measure protons scattered through very small angles is installed in the beam pipe far downstream of the interaction point. We describe the ATLAS Forward Proton AFP Detectors, including their performance to date, covering regular proton-proton data-taking as well as special LHC configurations like "the oxygen campaign". Finally, a glimpse on the newest results will be given.

Speaker: Tomasz Mróz (Institute of Nuclear Physics, Polish Academy of Sciences)

T.Mroz.DIS26.v0405.pdf

15:30 CMS is looking forward: boosting CMS capability for forward physics in HL-LHC

For LHC Run 4, CMS has planned substantial upgrades to enhance its forward-physics capabilities in proton–proton and heavy-ion collisions. To exploit the full potential of the HL-LHC datasets, a radiation-hard Zero-Degree Calorimeter and an upgraded Precision Proton Spectrometer, with new optics and improved high-pileup performance, have been designed. Following successful tests during Run 3 heavy-ion data taking, prospects for instrumenting the very-forward region with new forward scintillator counters covering $6<\eta<8$ are also being explored. In addition, the timing detector, by providing hadron PID down to low $p_T$ across a wide pseudorapidity range, will further enhance CMS’s capability to study photon-induced light and heavy-flavor probes with the highest experimental accuracy. This talk reviews the physics reach enabled by the upgrade program — from precision photonuclear and diffractive measurements in proton–proton, proton–ion, and ion–ion collisions to enhanced sensitivity for targeted BSM searches — and summarizes the detector specifications and implementation plans. We will also describe how these upgrades, together with enhanced L1 tracking triggers, extend the triggering and selection capabilities for UPC heavy-ion collisions.

Speaker: Michael Pitt (CERN)

DIS2026_CMS_Forward.pdf

15:50 PPS2: a new precision proton spectrometer for CMS at HL-LHC

The CMS experiment has been successfully operating the Precision Proton Spectrometer (PPS) since 2016 to study central exclusive production (CEP) events, pp→pXp, at the LHC via the detection of the surviving protons. CEP allows unique sensitivity to physics beyond the standard model, e.g. in the search for anomalous quartic gauge couplings, axion-like particles, and in general new resonances. Currently PPS operates near beam tracking and timing detectors installed at ~200m from the interaction point inside dedicated stations. Since in the next years the accelerator will undergo a significant upgrade towards very high luminosity performances (HL-LHC), the CMS collaboration recently decided to build a new proton spectrometer (PPS2) to continue the physics program profiting of the new high luminosity regime. The talk will describe the physics motivation of PPS2, the detector design and the challenges of the integration of the apparatus inside the new accelerator facility.

Speaker: Fabrizio Ferro (Istituto Nazionale di Fisica Nucleare)

CMS-PPS at HL-LHC - DIS26.pdf

16:15 → 16:30 Tea break - available from 16:00 to 17:00

16:30 → 18:30 WG2 Small-x, diffraction and vector mesons

Convener: Cristovao Fernandes Vilela

16:30 Nuclear suppression and proton geometry from diffraction, flow, and charge radius

Diffractive vector meson production provides a powerful probe of gluon saturation and the spatial structure of small-x gluons. Within the Color Glass Condensate (CGC) framework, it is sensitive to both nonlinear dynamics and event-by-event fluctuations in the proton wave function. HERA data, particularly for ${J/\psi}$ photoproduction, suggest that the gluonic radius of the proton is smaller than its charge radius.

We introduce a model for the spatial structure of the proton where the gluonic hot spots are distributed along Y-shaped color flux tubes, simultaneously reproducing charge and gluonic radii. The model is implemented in an impact-parameter-dependent McLerran–Venugopalan framework with JIMWLK evolution.

A combined Bayesian analysis of HERA and LHC ultraperipheral collision data shows that, while proton data are well described, nuclear cross sections are overestimated at high energies, indicating insufficient saturation effects. This tension can be mitigated by introducing an overall normalization factor that accounts for model uncertainties.
We present predictions for nuclear targets and show that both correlation observables and momentum-transfer-dependent cross-section ratios provide sensitive probes of proton geometry and can discriminate between different models in future measurements.

Finally we demonstrate how future ${\gamma}$+O and ${\gamma}$+Ne studies at the LHC or at the EIC can probe the structure of the light nuclei.

Speaker: Hendrik Roch (University of Jyväskylä)

05_05_26_DIS_Hendrik_Roch.pdf

16:50 Probing Gluon Saturation with Angular Correlations in Forward p-p and p-A Collisions

Dihadron angular correlations in forward proton–proton and proton–nucleus collisions offer a sensitive probe of gluon saturation effects, where both gluon saturation and parton shower dynamics contribute to the observed de-correlation between back-to-back hadron pairs. In this talk, we employ the Color Glass Condensate (CGC) framework to conduct a detailed numerical investigation of dihadron correlations at forward rapidities in p-p and p-A collisions at RHIC and the LHC. We adopt the improved Transverse Momentum Dependent factorization scheme tailored for small-$x$ physics and incorporate parton shower effects by the corresponding Sudakov factor. Our results show good agreement with STAR data. Additionally, we provide predictions for dihadron correlations for the FOCAL kinematic range at the LHC [1]. We also present full CGC calculations of heavy hadron correlations coupled with Sudakov resummation, which successfully describe di–D meson correlations over the entire angular range in p-p and p-Pb collisions at the LHC. We further demonstrate that heavy flavor observables are even more sensitive to gluon saturation effects than light hadrons [2]. We also discuss the extension of these dihadron correlation studies to electron–ion collisions.

[1] P. Caucal, Z. B. Kang, P. Korcyl, F. Salazar, B. Schenke, T. Stebel, R. Venugopalan and W. Zhao, [arXiv:2512.21466].
[2] F. Salazar, B. Schenke and W. Zhao, in preparation.

Speaker: Wenbin Zhao

Wenbin_Zhao_DIS_2026.pdf

17:10 Studying Gluon Saturation Effects in Forward Photon-Hadron Transverse Energy-Energy and Azimuthal Correlations in Proton-Proton and Proton-Lead Collisions at the LHC

We investigate gluon saturation signals in photon–hadron transverse energy–energy correlation (TEEC), along with the ordinary azimuthal correlations, in the forward rapidity region for proton–proton and proton–lead collisions, in the context of the HL-LHC upgrades, in particular the FoCal detector of ALICE which will cover 3.8 < η < 5.1 and the ATLAS detector with the extended coverage of |η| < 4. The calculations were performed using the CGC-based hybrid kT-factorization framework, implemented at parton level in KATIE and supplemented with initial and final-state radiation and hadronization effects simulated via CASCADE. We find both observables are sensitive to gluon saturation, however we explicitly find that the hadron-level TEEC distribution much better reflects the underlying parton dynamics than the ordinary azimuthal correlations. Based on: Phys. Rev. D 112, 114020.

Speaker: Ishita Ganguli (AGH University of Krakow)

DIS2026_IG.pdf

17:30 Probing Gluon Saturation with $J/\psi$ Spin Interference in Photoproduction at STAR

Heavy vector-meson photoproduction is a premier tool for imaging nuclear gluon distributions, traditionally via the momentum-transfer ($t$) dependence of exclusive cross sections. We show that in ultra-peripheral heavy-ion collisions (UPCs) the $J/\psi$ spin/decay angular structure provides a complementary handle for gluon tomography, enabled by the UPC ``two-source'' interferometer and linearly polarized photons.

We present the first evidence of spin-dependent interference in exclusive $J/\psi \to e^+e^-$ photoproduction in ultraperipheral Au+Au ($\sqrt{s_{NN}}=200$~GeV) and isobar (Ru+Ru, Zr+Zr, $\sqrt{s_{NN}}=200$~GeV) collisions at the STAR experiment. A significant negative $\cos(2\phi)$ modulation is observed for the $J/\psi$ at $p_T < 100$~MeV/$c$ with a combined significance exceeding $3\sigma$. Crucially, this sign is opposite to the positive modulation previously observed in $\rho^0 \to \pi^+\pi^-$ photoproduction. This result definitively resolves the ambiguity regarding the interference mechanism, demonstrating that the modulation sign is driven by the specific spin properties of the decay daughters (spin-1/2 fermions vs. spin-0 bosons).

Unlike the soft $\rho^0$ meson, the heavy $J/\psi$ mass scale ($M_{J/\psi} \gg \Lambda_{\mathrm{QCD}}$) allows us to probe the gluon spatial distribution at perturbative scales. We compare the measured modulation strength to Color Glass Condensate (CGC) calculations, showing that the data favor models incorporating linear photon polarization while ruling out scenarios dominated by soft-photon radiation. These findings establish $J/\psi$ spin interference as a novel, hard-scale probe of nuclear gluon structure, providing a critical baseline for future measurements at the EIC.

[1] STAR Collaboration, ``Evidence of Spin-Interference Effects in Exclusive $J/\psi \rightarrow e^+e^-$ Photoproduction in Ultraperipheral Heavy-Ion Collisions,'' arXiv:2512.02865 [nucl-ex]

Speaker: Prithwish Tribedy (Brookhaven National Laboratory)

prithwish_dis2026_v4.pdf

17:50 Studies of low-x phenomena with the LHCb detector

In heavy-ion collisions, collective phenomena in the hot and dense medium known as the Quark–Gluon Plasma (QGP) are probed through measurements of mean transverse momentum and azimuthal particle correlations. Similar correlation patterns observed in small collision systems raise questions about their origin, involving either final-state collective effects or initial-state parton correlations at small-x. The LHCb experiment has unique capabilities to study these observables at forward rapidity in high-energy hadronic collisions, accessing the smallest Bjorken-x values among the LHC detectors, where parton correlations are more pronounced. By comparing small to intermediate-x regions, the LHCb experiment also has unique sensitivity to initial-state effects. This contribution presents recent LHCb results on mean transverse momentum and collective flow in small systems, providing new constraints on the mechanisms driving particle correlations.

Speaker: Mr imanol corredoira (Universidade de Santiago de Compostela / IGFAE)

DIS_icorredo_final.pdf

18:10 Nucleon energy correlators at small x

In recent years, energy correlators have attracted renewed interest as powerful probes of QCD dynamics. Extending this concept to nucleon structure, nucleon energy correlators (NECs) offer a new avenue for imaging partonic dynamics through correlations between initial-state partons and energy flow in the target fragmentation region. In this talk, I will present an investigation of NECs at small $x$ in both the quark and gluon sectors. In particular, we establish a connection between T-odd NECs and the spin-dependent odderon, identifying them as novel probes of C-odd gluon dynamics. We also show that NECs provide a sensitive probe of linearly polarized gluons and saturation effects. Our study establishes NECs as promising observables for exploring small-$x$ dynamics at the future Electron–Ion Collider.

This talk is based on H. Mäntysaari, Y. Tawabutr, X.B. Tong, Phys.Rev.D 112 (2025) 11, 114027 and ongoing work.

Speaker: Xuanbo Tong

Tong_DIS2026_NEC.pdf

16:30 → 18:30 WG4 QCD with Heavy flavours and Hadronic Final States

16:30 System-size dependence of charged-particle nuclear suppression

High-energy partons produced in ultrarelativistic nucleus–nucleus collisions undergo energy loss while traversing the hot, strongly interacting medium, resulting in a suppression of high-transverse-momentum particle production. While this phenomenon is well established in heavy-ion collisions, its quantitative dependence on the size of the colliding nuclear system remains largely unconstrained. We present a systematic study of high-$p_{\mathrm{T}}$ charged-particle suppression across multiple collision systems using measurements of the nuclear modification factor, $R_{\mathrm{AA}}$. Previously published results in oxygen–oxygen, xenon–xenon, and lead–lead collisions are reanalyzed using a common $p_{\mathrm{T}}$ binning and are complemented by the first measurement of charged-particle $R_{\mathrm{AA}}$ in neon–neon collisions at $\sqrt{s_{\mathrm{NN}}}=5.36$ TeV. Presented as functions of $p_{\mathrm{T}}$ and the nuclear mass number $A$, the results span four systems and provide new constraints on the system-size dependence of parton energy loss, offering a unified experimental baseline for comparisons with QCD-based energy-loss models.

Speaker: Gian Michele Innocenti (MIT)

20260505_DISInnocenti_Upload.pdf

16:50 Recent PHENIX Results on Production and Hadronization of Heavy Quarks in $p+p$ and $p+$Au Collisions at RHIC

In high-energy hadronic collisions, heavy quarks are produced predominantly in the initial hard scatterings. $B$-mesons, which are composed of a bottom antiquark and another type of a light quark can then undergo a variety of decays, and studying these decays provides valuable insights on QCD mediums produced by the collisions. In this talk, the PHENIX experiment presents first of all a new measurement of the beauty contribution to inclusive $J/\psi$ production in $p+p$ collisions. $J/\psi$ mesons from $B$-meson decays are statistically separated from prompt $J/\psi$ using displaced decay vertices. The fraction of $B$$\rightarrow$ $J/\psi$ is measured over wide transverse momentum and rapidity ranges and compared with results from other experiments and theoretical calculations based on FONLL combined with the color evaporation model. It should be pointed out that this result is the first to directly access the total bottom quark cross section in the mid-rapidity region at RHIC. Secondly, new measurement of $J/\psi$ production as a function of event multiplicity in p+p and p+Au collisions is presented. The charmonium yield and event activity are measured in different combinations of rapidity regions, reducing auto-correlation effects and enabling studies of nuclear medium effects on $J/\psi$ production and hadronization over different Bjorken-x regimes. Together, these two measurements establish a comprehensive framework for understanding heavy-quark production and hadronization in nuclear collisions at RHIC energies.

Speaker: Rachid Nouicer (Brookhaven National Laboratory)

PHENIX_DIS2026_Rachid_Nouicer_F.pdf

17:10 In medium evolution of the energy-energy correlators

In this work we present a first-principles analysis of the scale evolution of the two-point energy-energy correlator (EEC) for quark and gluon jets propagating through QCD matter. The EEC is a jet substructure observable that encodes the angular distribution of energy flow within jets and has proven valuable for precision tests of QCD in elementary collisions. Extending this framework to reactions with nuclei, we derive a factorized description of the in-medium EEC using Soft Collinear Effective Theory with Glauber gluon interactions, allowing systematic inclusion of medium-induced interactions. Working in the opacity expansion, we compute the medium-modified quark and gluon jet functions at one loop and perform leading-logarithmic resummation of large-scale logarithms. We find an experimentally accessible kinematic regime where medium effects manifest directly through medium-induced corrections to the anomalous dimensions, providing a transparent probe of in-medium dynamics. We test the theoretical framework by comparing our analytic predictions with EEC measurements in p–Pb collisions and discuss its implications for small collision systems and the EIC.

Speaker: Weiyao Ke (Central China Normal University)

Weiyao-Ke-DIS26-May-05-Version-2.pdf

17:30 Nuclear Modification of Identified Hadrons in Small Collision Systems at RHIC

In this talk we will report measurements of identified charged hadron production within reconstructed jets in proton-proton (p+p), proton-aluminum (p+Al), and proton-gold (p+Au) collisions at $\sqrt{s_{NN}}$ = 200 GeV recorded by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Charged hadrons are reconstructed with the Time Projection Chamber (TPC) and Time-of-Flight (TOF) detectors and identified as pions, kaons, or protons via combined ionization energy loss and timing information. Jets are reconstructed using the anti-$k_T$ algorithm with well-defined acceptance and quality cuts. Identified hadron yields inside jets are studied as functions of the momentum fraction $z$ and the transverse momentum $j_T$ relative to the jet direction. Per-jet hadron yields are normalized and measured for each collision system using a consistent jet and track selection, thereby reducing sensitivity to luminosity and efficiency effects. Ratios of the per-jet yields in p+A to those in p+p collisions will be used to quantify possible nuclear modifications of jet fragmentation functions, providing insight into parton energy loss and hadronization in cold nuclear matter, and offering new experimental constraints on parton fragmentations in small systems at RHIC energies.

Speaker: Gabriel Garcia (Brookhaven National Laboratory)

GabrielGarcia_DIS2026_v4.pdf

17:50 Measurements of correlations between $Z$ bosons or $\Upsilon$ mesons and inclusive charged particles in small systems with ATLAS

Recent studies from various experiments at the LHC and RHIC suggest that small collision systems exhibit quark-gluon plasma (QGP)-like signatures similar to those previously observed in large systems. While QGP-like signatures have been observed in the soft sector, strong constraints on possible partonic energy loss were established in the hard sector. At the same time, there are multiple pieces of evidence pointing to correlations between hard and soft particle production in proton-proton collisions. The search for energy loss in small systems can be expanded to very low transverse momentum by studying charged hadrons correlated with $Z$ bosons, thus obtaining a proxy for low-energy jets. The initial condition of the hard probe is controlled via the kinematics of the leptonically decaying $Z$ boson, which is unaffected by the QGP due to the absence of color charges. Results from ATLAS on the hadron production in events with $Z$ bosons in $p$+Pb and $pp$ collisions at $\sqrt{s_{\mathrm{NN}}} 8$~TeV are presented. For the first time, these results are separated between the underlying event and hard scattering components, and a relation between the two is discussed.

The correlations between hard and soft particle production in $pp$ collisions are studied in events with $\Upsilon$ mesons, which provide a valuable hard probe to study such effects. The multiplicity and distributions of kinematic variables of charged particles produced in association with an $\Upsilon$ meson are measured using 139 fb$^{-1}$ of data at $\sqrt{s}\ = 13$~TeV collected by the ATLAS experiment at the LHC. The measurement is performed separately for the first three $\Upsilon$(nS) states in intervals of their transverse momentum.
At low transverse momentum, the associated charged-particle multiplicity is observed to be systematically lower in collisions where $\Upsilon$(2S) or $\Upsilon$(3S) is produced compared to $\Upsilon$(1S), with the difference decreasing as the $\Upsilon$ transverse momentum increases. The study also includes measurements of $\eta-\phi$ correlations between $b\bar{b}$ states and charged particles.

Speaker: Baidyanath Sahoo (Weizmann Institute of Science)

DIS26_baidya.pdf

18:10 Double quarkonium production in hadronic collisions at fixed-target experiments

In this talk, we present new results for double quarkonium production in (un)polarized hadronic collisions at fixed-target experiments. Our approach incorporates the transverse momentum dependent factorization in combination with the Color-Singlet Model. We present new analytical expressions for the angular structure of the cross section for the
$q \bar q$-induced channel, and provide predictions for the unpolarized cross section and transverse single-spin asymmetries for present and future fixed-target experiments at CERN and the LHC.

Speaker: Carlo Flore (Università di Cagliari e INFN, Sezione di Cagliari)

talk-Flore-di-onium-DIS-2026.pdf

16:30 → 18:20 WG5 Spin and 3D-structure

Convener: Jan Matousek (Charles University, Prague)

16:30 Nucleon Tomography with 0-jettiness

We propose a novel strategy to systematically isolate the nucleon’s intrinsic non-perturbative three-dimensional structure by employing 0-jettiness to suppress initial-state radiation in transverse momentum-dependent (TMD) observables. Applying this method to transverse single spin asymmetries (SSAs) in $W_±$ and $Z_0$ boson production at RHIC, we demonstrate a substantial enhancement of the asymmetry signal (e.g., by 83% for $Z_0$ SSA at $q_\perp$ = 5 GeV), enabling a more definitive test of the predicted sign change of the Sivers function–a key prediction of TMD factorization. We further explore its applicability to spin-dependent measurements at the Electron-Ion Collider. Our analysis is formulated within a joint resummation framework that systematically resums large logarithms associated with both the veto scale and the gauge boson’s transverse momentum.

Speaker: Shuo lin (Shandong University)

DIS shuo lin.pdf

16:50 Collins effect in pion-in-jet production in polarized $pp$ and $ep$ collisions

The production of light hadrons within jets in polarized $pp$ and $ep$ collisions represents a promising tool to probe transverse momentum dependent (TMD) effects. As for the TMD factorizable processes (Drell-Yan, semi-inclusive DIS and $e^+ e^-$ annihilation into hadron pairs), such a reaction shares common features with them, the presence of two ordered energy scales: a large one, the transverse momentum of the jet, and a small one, the intrinsic transverse momentum of the light hadron with respect to the jet direction. In this regard, this process represents an interesting proxy to study TMD factorization and the universality of TMD distributions.

In this talk, we present recent and ongoing phenomenological analyses on the Collins azimuthal asymmetries in $p^\uparrow p \to {\rm jet}\,\pi\, X $ and $e p^\uparrow \to {\rm jet} \pi X $ collisions within the TMD approach. By adopting recent extractions of the transversity and the Collins fragmentation function from semi-inclusive DIS and $e^+ e^- \to h_1 h_2 X$ processes, we present a comparison with recent STAR data for pp collisions, and predictions for the future Electron-Ion Collider for lepton-proton collisions in the quasi-real photon regime.

Speaker: Carlo Flore (Università di Cagliari e INFN, Sezione di Cagliari)

talk-Flore-pion-in-jet-DIS-2026.pdf

17:10 Transverse momentum and azimuthal angle distributions of hadrons in DIS at COMPASS

The COMPASS experiment plays an important role in studies of nucleon structure. Measurements performed in 2016–2017 with an unpolarised liquid hydrogen target and a longitudinally polarised 160 GeV/$c$ muon beam provide a high-statistics data sample for the analysis of semi-inclusive deep-inelastic scattering, giving access to transverse-momentum-dependent parton distribution and fragmentation functions.
The 2016 data set was analysed to determine the multiplicities of hadrons produced in DIS differential in $x$, $Q^2$, $z$ and $P_\text{T}$, as well as the amplitudes of modulations in their azimuthal-angle distributions. In particular, the unpolarised asymmetries $A^{\cos \phi_\text{h}}_\text{UU}$ (related to the Cahn effect), $A^{\cos 2\phi_\text{h}}_\text{UU}$ (sensitive to the Boer–Mulders function), and the beam-spin asymmetry $A^{\sin \phi_\text{h}}_\text{LU}$ were extracted in 4-dimensional bins matching those of the multiplicities, and also integrated over some of the variables.

Speaker: Vendula Benešová (Charles University)

Benesova_DIS_2026.pdf

17:30 Testing Factorization and Universality of the Collins Asymmetry with $p^{\uparrow}$+Au Collisions at STAR

We report a preliminary measurement of the Collins azimuthal asymmetry for identified charged pions within jets in transversely polarized proton--gold collisions at $\sqrt{s_{NN}}=200$ GeV using the Relativistic Heavy Ion Collider (RHIC) and recorded by the Solenoidal Tracker At RHIC (STAR) detector. In the Transverse-Momentum-Dependent (TMD) framework, the Collins modulation $A_{UT}^{\sin(\phi_S-\phi_H)}$ provides access to the product of the quark transversity distribution and the Collins fragmentation function, and thus probes transverse spin--momentum correlations in QCD hadronization. On the one hand, general arguments have been put forth that there should be factorization breaking of TMDs in $pp$ collisions. But on the other hand, detailed calculations imply the Collins asymmetries in $pp$ collisions and semi-inclusive deep-inelastic scattering are the same. A central motivation of this measurement is to test the robustness and universality of the Collins mechanism and associated TMD factorization in a nuclear environment, where additional color interactions could in principle modify the observed asymmetry compared to that seen in $pp$ collisions.

Speaker: Bassam Aboona (Texas A&M University)

BassamAboona_DIS2026_final.pdf

17:50 Dijet probes for initial state effects in p+A collisions at ATLAS

Proton–nucleus collisions at the LHC provide a powerful laboratory to investigate initial-state phenomena in heavy-ion physics. Fluctuations in the proton configuration can significantly modify its effective interaction strength, biasing estimates of event activity and, consequently, the inferred number of wounded nucleons in the Pb nucleus.
In this context, dijets offer a particularly sensitive probe, as they enable a precise characterization of the initial-state kinematics of the hard scattering. In this talk, we present recent ATLAS results studying the role of proton configurations in p+A collisions, using dijet events in p+Pb collisions at $\sqrt{s_{NN}} = 8.16$ TeV collected in 2016.
The results investigate correlations between event activity, forward neutron production, and the initial-state kinematics of the hard process, providing new evidence for the role of proton shape fluctuations in these collisions. These measurements provide the first quantitative input toward exploring the relationship between hard scattering processes and nuclear breakup.
The data offer new opportunities to link proton spatial configurations, typically characterized via generalized parton distribution functions, with nuclear breakup and the overall interaction strength in p+A reactions.

Speaker: Patrik Novotný (Weizmann Institute of Science (IL))

DiS_slides_final.pdf

16:45 → 18:05 WG1 Structure functions and parton densities

Convener: Thomas Cridge (University of Manchester)

16:45 nCTEQ global analysis of nuclear PDFs

We present a new global analysis of nuclear PDFs in the nCTEQ approach. Building on a modern proton baseline without nuclear data and extending the kinematic range, we combine and update previous separate analyses that focused on JLab neutral-current DIS, neutrino DIS and dimuon production, and the currently available LHC data, in particular on W/Z-boson and heavy-quark production. For the latter, we not only employ a data-driven approach, but also perform an alternative fit based on NLO QCD and the ACOT variable flavour number scheme. As a result, we obtain PDFs with reduced uncertainties in both the high-x and low-x regimes, in particular for the gluon and the strange quark. We also present predictions for observables that were not included in this analysis.

Speaker: Tomas Jezo (University of Münster)

TJezo_DIS26_WG1.pdf

17:05 Impact of Open Heavy-Flavour Production on nCTEQ Nuclear PDFs

We present a dedicated analysis of nuclear PDFs that focuses on open heavy-flavour production in pA collisions. Using a larger heavy quark data set than in the baseline fit, we quantify the resulting constraints on nuclear PDFs, with particular sensitivity to the gluon modification in the shadowing region. We rely on perturbative QCD in the SACOT general-mass-variable-flavour-number scheme to describe the data and compare it to the previously used data-driven Crystal-Ball approach. To make repeated NLO computations feasible, we accelerate the calculations with PineAPPL fast-interpolation grids, enabling direct SACOT predictions in the fit.

Speaker: Mr Jan Wissmann (University of Münster)

wissmann_dis2026.pdf

17:25 Nuclear modifications on longitudinal-transverse structure function ratio in the deuteron

It has been assumed that nuclear modification does not exist in the longitudinal-transverse structure function ratio $R_N=F_L^N/(2xF_1^N)$ in lepton deep inelastic scattering. This assumption is widely used in obtaining structure functions of the ``nucleon" from nuclear data such as the deuteron ones. However, nuclear modifications do exist theoretically at least at medium- and large-$x$ regions because nucleons in a nucleus move in any direction, which is not necessary the longitudinal direction of the virtual-photon or weak-boson momentum in lepton scattering. Because of this transverse motion, the nucleon's transverse and longitudinal structure functions should mix with each other in nuclei with the mixture probability proportional to the nucleon's transverse momentum squared $\vec p_T^{\,\, 2}/Q^2$. In this work [1], numerical results are explicitly shown on such nuclear modifications in the deuteron. These nuclear modifications are important for determining precise structure functions of the nucleon. Furthermore, modifications of $R_N$ should be investigated also at small $x$ by the future electron-ion collider to find interesting gluon dynamics in nuclei. Hopefully, this nuclear effect on $R_N$ could be found by future experimental measurements at lepton accelerator facilities.

[1] S. Kumano, arXiv:2506.18305, Phys. Rev. C in press.

Speaker: Prof. Shunzo Kumano (IMP/KEK)

Kumano-R-mod-DIS2026-2026-05.pdf

17:45 Nuclear modifications of parton distributions

A quantitative explanation of the effects observed in nuclear DIS requires the presence of an in-medium nuclear modification of parton distribution functions, extending beyond the traditional Fermi motion and binding correction. We will discuss nuclear DIS basing on a microscopic model [1] taking into account the energy-momentum spectrum of bound nucleons, off-shell modification of bound nucleon structure functions, corrections from meson-exchange currents as well as the corrections from propagation of quark-gluon states in nuclear environment. The off-shell correction, which provides a mechanism of the modifications of the partonic structure in bound protons and neutrons, can be constrained from a global QCD analysis together with the PDFs in the proton. The new data from MARATHON experiment on the EMC effect for 3He/2H and 3H/2H allows to better constrain F2n/F2p in the region of large Bjorken x, as well as to improve the accuracy in the determination of the isoscalar nucleon off-shell function, its proton-neutron asymmetry, and ts interplay with the higher-twist terms in the structure functions. We discuss a number of applications including lepton-nucleus DIS, Drell-Yan production in proton-nucleus collisions, and $W^\pm, Z^0$ boson production in p+Pb collisions at the LHC.

References

[1] S.A. Kulagin and R. Petti, Nucl. Phys. A765 (2006) 126.
[2] S.I. Alekhin, S.A. Kulagin, R.Petti, Phys. Rev. D96 (2017) 054005.
[3] S.I. Alekhin, S.A. Kulagin, R.Petti, Phys. Rev. D105 (2022) 114037.
[4] S.I. Alekhin, S.A. Kulagin, R.Petti, Phys. Rev. D107 (2023) L051506.

Speaker: Roberto Petti

DIS26-Petti.pdf

16:45 → 19:10 WG3 Electro-weak physics/higgs/top and BSM: Flavor physics

Conveners: Ken Mimasu (University of Southampton), Menglin Xu

16:45 Perturbative QCD Prediction of the Hyperon EDM from CP-violating Dipole Interactions (17'+3')

Electric dipole moment (EDM) of baryons provides a sensitive probe of CP-violating interactions beyond the Standard Model. Motivated by the recent BESIII measurement on the $\Lambda$-hyperon EDM, we present the first perturbative QCD analysis of the $\Lambda$ EDM form factor to elucidate its origin in CP-violating quark dipole interactions. In particular, we derive a QCD factorization formula that relates the $\Lambda$ EDM form factor to quark EDMs and chromo-electric dipole moments (CEDMs) through convolutions with light-cone distribution amplitudes of $\Lambda$. These connections allow us to extract constraints on CP-violating dipole couplings from current and future hyperon EDM measurements. Our numerical analysis demonstrates that the $\Lambda$ EDM exhibits unique sensitivity to the strange-quark CEDM, providing complementary information to that obtained from the neutron EDM.

Reference: K.B. Chen, X.G. Xiao, J.P. Ma, X.B. Tong, arXiv:2509.22087

Speaker: Xuanbo Tong

Tong_DIS2026.pdf

17:05 New physics searches in beam dump at NA62 (22'+3')

The NA62 experiment at CERN, designed to measure the highly-suppressed decay $K^{+} \to \pi^{+}\nu\bar{\nu}$, has the capability to collect data in a beam-dump mode, where 400 GeV protons are dumped on an absorber. In this configuration, New Physics particles may be produced in the absorber and decay in an instrumented volume beginning approximately 80 m downstream of the dump. Preliminary results from a search for Heavy-Neutral leptons decaying in flight to semi-leptonic final states are reported, based on an analysis of a sample of $6.2 \times 10^{17}$ protons on dump collected in 2021, 2023, and 2024.

Speaker: Daniel Grewe

DIS2026_NA62_Beamdump.pdf

17:30 New measurement of $K^{+} \rightarrow \pi^{+}\nu\bar{\nu}$ branching ratio at the NA62 experiment (22'+3')

The $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ decay is a golden mode for flavour physics. Its branching ratio is predicted with high precision by the Standard Model to be less than $10^{-10}$, and this decay mode is highly sensitive to indirect effects of new physics up to the highest mass scales. Using data collected in 2016--2022 NA62 announced the first observation of this decay with a significance in excess of 5 sigma. New results from the analysis of the 2023--2024 dataset are presented. This dataset doubles the effective sample size. Reconstruction and selection algorithms have been improved, boosting sensitivity and reducing the background contamination. An updated measurement of the $K^{+}\rightarrow\pi^{+}\nu\bar{\nu}$ branching ratio is presented and prospects for the full 2016–2026 dataset are discussed.

Speaker: Tommaso Spadaro (Istituto Nazionale di Fisica Nucleare)

Spadaro_DIS2026_NA62_5_5_2026.pdf

17:55 Latest Results from the SND@LHC Experiment (17'+3')

SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < 𝜂 < 8.6,
complementary to all the other experiments at the LHC. The experiment is located 480 m downstream of IP1 in the unused TI18 tunnel.
The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers,
followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours,
opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb.
This region is of particular interest also for future circular colliders and for predictions of very high-energy atmospheric neutrinos.
The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target.
Since 2022 the experiment has collected 309 fb-1 of data at 97% efficiency. Using data from the electronic detectors,
muon neutrino interactions were found as well as solid evidence for electron neutrino interactions.
In this talk we shall present results from 2025 data, including an analysis of the muon flux which has significantly increased our understanding of the behaviour of the LHC beams.
The reconstruction of the emulsion data has now achieved a sub micrometer resolution and significant progress was made with vertex finding and electronic shower recognition

Speaker: Cemal Dinç (Middle East Technical University (TR), SND@LHC Collaboration)

DIS_2026_final.pdf

18:15 Charged-current semileptonic b-hadron decays at LHCb: precision tests with heavy-flavour QCD inputs (17'+3')

Charged-current semileptonic b-hadron decays are a prime arena for precision tests of the Standard Model and sensitive probes of physics beyond it. At LHCb, large heavy-flavour yields enable measurements of both high-rate modes (with light leptons) and lepton-universality–testing channels with taus, alongside detailed studies of differential and angular observables. Interpreting these results hinges on non-perturbative QCD information, most notably hadronic form factors and their shapes, whose uncertainties directly propagate into extractions of CKM parameters and effective-field-theory constraints on short-distance couplings. This contribution presents a selection of recent LHCb results on b → c ℓ ν decays (ℓ = μ, τ), highlighting their impact on global phenomenology and emphasizing the role of heavy-flavour QCD inputs in controlling the dominant theory systematics.

Speaker: Sofia Zalambani (Istituto Nazionale di Fisica Nucleare)

DIS26_ZS.pdf

18:35 Simultaneous determination of the CKM angle gamma and parameters related to mixing and CP violation in the charm sector at LHCb (8')

A precise measurement of the CKM angle $\gamma$ is a standard candle measurement of CP violation in the Standard Model and a central goal of the LHCb experiment. The latest LHCb results from measurements of CP violation using beauty to open charm decays are presented. These include novel measurements and the latest LHCb combination of $\gamma$ and charm mixing measurements.

Speaker: Alessandro Bertolin (Istituto Nazionale di Fisica Nucleare)

DIS 2026 bertolin.pdf

DIS 2026 bertolin.pptx

16:45 → 18:15 WG6 Current upgrades and future experiments

Convener: Federico Lasagni Manghi (Istituto Nazionale di Fisica Nucleare)

16:45 Precision Timing with the CMS MIP Timing Detector for High-Luminosity LHC

In the upgrade of the CMS apparatus for the HL-LHC, an innovative MIP Timing Detector (MTD) will provide unprecedented time measurement capabilities for charged particles. Different sensor technologies will be used in its barrel section, made of LYSO:Ce crystals read by SiPMs, and its endcap, equipped with silicon low-gain avalanche diodes. In both cases, custom ASICs will provide the required output information to achieve a time resolution of O(30 ps) at the beginning of operations per charged track. The primary goal of this information is to mitigate the increased pileup compared to the LHC, while maintaining the competitive performance of the physics reconstruction algorithms. Particle identification will be a natural by-product of proton-proton collisions and will be the main goal of MTD for Heavy-Ion physics. In addition, time measurements will be a new tool for several types of new physics searches. To make this program possible, several developments in detector simulation, reconstruction algorithms, and calibration procedures are being actively pursued to lay the foundations for the realistic use of this innovative detector within a few years. This talk presents an overview of the detector, its construction status, and recent results on the preparation for its commissioning and physics exploitation.

Speaker: Licheng Zhang

CMS-MTD-DIS-2026-Licheng-Zhang.pdf

17:05 LUCID, the ATLAS luminosity detector in LHC Run-3 and its upgrade for HL-LHC

The LUCID-2 detector is the main luminometer of the ATLAS experiment and the only one able to provide a reliable luminosity determination in all beam configurations, luminosity ranges and at bunch-crossing level. During LHC Run-2 ATLAS has measured luminosity with a precision of 0.8%, the most precise ever among all experiments running at a hadron collider. LUCID-2 is now providing ATLAS with the luminosity measurement also in LHC Run-3. Preliminary results on the acquired datasets will be presented, suggesting that a similar precision can be obtained. The ATLAS physics program at High Luminosity LHC (HL-LHC) calls for a precision in the luminosity measurement of 1%. To fulfill such requirement in an environment characterized by up to 140 simultaneous interactions per crossing (200 in the ultimate scenario), ATLAS will feature several luminosity detectors. At least some of them must be both calibratable in the van der Meer scans at low luminosity and able to measure up to its highest values. LUCID-3, the upgrade of LUCID will fulfill such a condition. In this contribution, two options for LUCID-3 under study are presented: the first is based on photomultipliers (PMT), as for LUCID-2, located farther from the beam-pipe to reduce the acceptance and avoid the detector saturation; the second is based on optical fibers acting as Cherenkov radiators and read-out by PMTs located in a low radiation area. All PMTs will be monitored by a radioactive 207Bi source to ensure long-term stability to better than 1%. An upgrade of the readout electronics will also be needed. The status of the analysis of the data acquired in Run-3 with prototypes of both technologies installed in ATLAS will be presented focusing on the possible final LUCID-3 design.

Speaker: Vincent Hedberg (Lund University)

LUCID.pdf

17:25 The ATLAS ITk Detector: design and expected performance

The ATLAS experiment is currently preparing for an upgrade of the Inner Tracking for High-Luminosity LHC operation, scheduled to start in 2030. The radiation damage at the maximum integrated luminosity of 4000/fb implies integrated hadron fluencies over 2x1016neq/cm2 and tracking in a very dense environment call for a replacement of the existing Inner Detector. An all-silicon Inner Tracker (ITk) is proposed with a pixel detector surrounded by a strip detector. After an extensive prototyping phase, all the institutes involved in the ITk are currently in pre-production phase, moving toward production mode. In this contribution we present the design of the ITk Detector and its expected performance. An overview of the current status of the various detector components, both pixel, strip and the other common items, focusing on the preparation for production, with its more challenging aspects, will be summarized.

Speaker: Hao Pang

DIS2026.pdf

17:45 Phase-II Physics Program of the AMBER Experiment at CERN

The AMBER experiment at CERN represents a next-generation fixed-target QCD facility designed to investigate the internal structure and dynamics of hadrons with unprecedented precision. In the middle of the data taking for the Phase-I program, AMBER presently focused on focused on antiproton production cross sections, high-precision determinations of the proton charge radius, and studies of pion structure via Drell–Yan and charmonium production. Phase-II will extend the physics reach using an intense high-energy hadron beam made possible by an upgraded M2 beam line at SPS, exploiting the kaons and antiprotons in the beam. The program under development will target, among others:
• measurements in the strange quark sector, such as the excitation spectrum of strange mesons, precision spectroscopy of kaon resonances, and searches for exotic hadronic states inaccessible in current datasets,
• precision measurements of the kaon charge radius via elastic scattering processes,
• measurement of the partonic structure of kaons through prompt photon and kaon-induced Drell–Yan production, complement existing data on pions and protons, providing critical input for global hadron structure studies.
The AMBER Phase-II program thus opens a new frontier in strong-interaction physics, expanding the experimental reach into the strange-quark domain with implications for QCD phenomenology and hadron spectroscopy

Speaker: Prof. Andrea Bressan (Istituto Nazionale di Fisica Nucleare)

amber_bressan_dis.pdf

amber_bressan_dis.pptx

18:05 Preliminary cooling tests for the ePIC Silicon Vertex Tracker Inner Barrel

The future Electron–Ion Collider (EIC) will offer a unique opportunity to explore parton distributions
inside nucleons and nuclei thanks to unprecedented luminosity, a wide range of energies,
a large choice of nuclear species, and polarization of both beams (in the case of light hadrons).
The electron–Proton–Ion Collider (ePIC) detector will enable, among other performance goals, precise determination of the positions
of primary and secondary vertices, which is essential, for example, for the identification of charm hadrons
with typical decay lengths of the order of 100 microns. This capability, achieved via topological selections,
provides access to the gluon distribution inside nucleons.
This measurement performance is ensured by the Silicon Vertex Tracker (SVT), the innermost detector of the ePIC experiment.
The SVT Inner Barrel (IB) adopts 65 nm MAPS (Monolithic Active Pixel Sensor) technology with stitching, pioneered by the ALICE
collaboration for the ITS3 upgrade, resulting in the MOSAIX sensor. This technology is employed to build three layers
of wafer-scale sensors, bent into a cylindrical shape thanks to their reduced thickness.
The low power density of the MOSAIX sensor allows cooling by airflow, which represents a significant advantage
in reducing the material contribution of service components within the detector and, consequently,
limiting multiple scattering that degrades tracking and vertexing resolution.
The stringent space and material budget constraints require careful design of the support structures and cooling system components,
which must ensure uniform temperature distribution over the sensor surface and adequate redundancy.
An additional challenge is posed by the presence of the Left End Cap (LEC), hosting the front-end electronics
for power distribution and data transmission, which introduces a localized region of higher power density at one edge of the sensor.
A dedicated test campaign was carried out using dummy heat loads in a closed setup, reproducing the MOSAIX power dissipation,
including the LEC contribution. The setup allows tunable airflow and power consumption and includes multiple
temperature sensors placed at critical locations along the sensor. The main goal of the tests was the optimization
of airflow and heat removal from regions characterized by different power densities.
A possible solution based on 3D-printed aluminum heat sinks produced via additive manufacturing was investigated.
Key design aspects of the dissipators include minimization of the material budget—targeting an impact comparable
to or lower than that of carbon foam, currently the baseline solution—and control of the airflow, which must transition
to a turbulent regime shortly after the air outlet and ensure uniform mass flow over the sensor surface.
The effect of thermal grease on the thermal coupling of the dissipators was also studied.
Several shapes of air distributors and aluminum heat sinks were tested, and first conclusions on their effectiveness were drawn.
The current status of the cooling system design and initial results from tests
performed on thermal mock-ups of silicon sensors are presented.

Speaker: Sabrina Ciarlantini (Istituto Nazionale di Fisica Nucleare)

DIS_Ciarlantini_presentation.pdf

Wednesday 6 May

09:00 → 10:45 WG1 Structure functions and parton densities

Convener: Paul Newman

09:00 sPHENIX measurements of jet and isolated photon production in p+p collisions at RHIC

The sPHENIX experiment is a next-generation collider detector at RHIC designed for rare jet and heavy flavor measurement in a variety of hadronic collision systems. The experiment includes large-acceptance, electromagnetic (EMCal) and hadronic (HCal) calorimeter systems, along with a very high-rate data acquisition plus trigger system. In RHIC Run-24, sPHENIX sampled 107/pb of p+p collision data at 200 GeV using efficient high-p$_T$ jet and photon triggers. This dataset represents a major increase in the luminosity times acceptance compared to previous measurements for this collision energy, along with the first HCal at mid-rapidity at RHIC for measuring the contribution from neutral hadrons to jets and to the photon isolation energy. This talk will report preliminary measurements of hard scattering processes, including reconstructed jets and isolated photons, over an extensive range of initial parton kinematics. The results, which can provide constraints on the proton PDFs in an extreme region up to Bjorken-x ~ 0.7, will also include comparisons to modern pQCD calculations.

Speaker: Yeonju Go (Brookhaven National Laboratory)

20260506_DIS_YeonjuGo.pdf

09:20 Probing the Light-Quark Ratio via Forward–Backward Asymmetry

In studies of proton structure and global parton distribution function (PDF) analyses, the ratio of down to up quarks remains poorly constrained by experimental data. This is because the contributions of these two light quarks are typically entangled in physical processes and are difficult to disentangle in final-state observables. In this talk, we present a recently proposed method that enables a direct probe of the light-quark ratio through the forward–backward asymmetry (AFB) of the Drell–Yan process at hadron colliders. In this approach, the down- and up-quark contributions to AFB are factorized and defined as new structure parameters, which can be directly measured as experimental observables. We will focus on the underlying idea of this method, recent experimental results from both the Tevatron and the LHC over the past three years, and the impact of these new measurements on global PDF analyses. In particular, results for the new structure parameters obtained from Tevatron and LHC data—corresponding to pure proton–proton or proton–antiproton interactions—indicate an enhancement of the valence down–to–valence up quark ratio relative to current PDF predictions. Equivalently, these results suggest that the ratio of anti-down to anti-up quarks (the SU(2) flavor asymmetry) is reduced and approaches unity. This finding is in tension with previous results extracted from deuteron data, such as those from the NuSea and SeaQuest experiments. Beyond providing an important new insight into proton structure, these results also cast doubt on the common assumptions of small nuclear corrections in deuteron targets and exact proton–neutron isospin symmetry.

[*for the conference committee, we provide the corresponding references of these works:

Phys. Rev. D 106, 033001 (2022)
Phys. Rev. D 107, 054008 (2023)
Phys. Rev. D 110, L091101 (2024)
arXiv:2505.17608
arXiv:2510.08941]

Speaker: Mr Wenhao Ma (University of Science and Technology of China)

protonStructure.pdf

09:40 Recent hard and soft QCD measurements in ATLAS

LHC offers diverse means to investigate the fundamental properties of QCD in hard and soft regimes. This talk presents a few latest QCD results in ATLAS, covering precision scrutiny with single vector bosons, measurement of vector boson and flavored jets, measurement of di-jet events, as well as probe of minibias production in pO collisions.

Speaker: Zdenek Hubacek (Czech Technical University in Prague)

ATL-COM-PHYS-2026-193.pdf

10:00 Measurements of $W^+$ and $W^-$ cross sections and their ratio in $pp$ collisions at STAR

While the unpolarized valence quark ($d$ and $u$) distributions are well determined from DIS and $pp/p\bar{p}$ experiments, their sea (anti-)quark counterparts, $\bar{d}$ and $\bar{u}$, are much less constrained, in particular, near the valence region (momentum fraction, $x \sim 0.2$).
Measurements of $W^+$ and $W^-$ production in $pp$ collider experiments can be used to probe the $\bar{d}$ and $\bar{u}$ at a large $Q^2$ set by the $W$ mass.
Presented in this talk are the latest updates of $W^+$ and $W^-$ cross sections and their ratio using the STAR $pp$ collision data at the center-of-mass energy of $\sqrt{s} = 510\,\mathrm{GeV}$ collected in 2017, corresponding to an integrated luminosity of $350\,\mathrm{pb^{-1}}$.
The measurements were performed by tagging leptons from the weak decay channel ($W \rightarrow e\nu$) arising from the mid $(|\eta|<1)$ and intermediate rapidities $(1 < \eta < 1.5)$, probing the $\bar{d}$ and $\bar{u}$ within the proton momentum fraction range of $0.06 < x < 0.4$.
These measurements will improve the precision of the previous measurements performed with the STAR 2011, 2012, and 2013 data.
A status update for the STAR 2022 $pp \;\sqrt{s} = 510 \;\textrm{GeV}$ dataset will be presented.

Speaker: Bernd Surrow (Temple University)

BSurrow-DIS2026_W_STAR_FINAL.pdf

10:20 Strangeness in the proton from $W^+$ charm production and SIDIS data

We perform a global QCD analysis of unpolarized PDFs in the proton, including new $W+$charm production data from $pp$ collisions at the LHC and semi-inclusive pion and kaon production data in lepton-nucleon DIS, both of which have been suggested for constraining the strange quark PDF. Compared with a baseline global fit that does not include these datasets, the new analysis reduces the uncertainty on the strange quark distribution over the range $0.01 < x < 0.3$, and provides a consistent description of processes sensitive to strangeness in the proton. The data place more stringent constraints on the strange asymmetry $s − \bar{s}$, which is found to be consistent with zero in this range.

Speaker: Wally Melnitchouk (Jefferson Lab)

melnitchouk-strange.pdf

10:30 Associated W + charm production: indications for PDF analysis

The simultaneous production of a $W^\mp$ boson and a charmed hadron $D^{(*)\pm}$ in proton-proton collisions, recently measured by ATLAS at $\sqrt{s} = 13$ TeV, offers a potential probe for constraining the strange quark distribution and studying strangeness asymmetry. By considering the production ratio of oppositely charged mesons, scale and fragmentation uncertainties become negligible. We present results for this ratio as functions of $p_T$ of the meson and $\eta$ of the charged lepton from the $W^\mp$ decay, computed using NLO general-mass perturbative QCD with scale-dependent fragmentation functions and three different PDF sets. The analysis shows good agreement between the ATLAS data and the CT18A and MSHT20 PDFs. In contrast, a significant tension is found for NNPDF40, with $\chi^2 / \#\text{d.o.f.} \approx 4$. Interpretation of the results proves difficult: on one hand, reweighting of MSHT20 indicates an increase in the magnitude of the strangeness asymmetry across most of $x$ space, while on the other hand, CT18A contains no strangeness asymmetry to begin with. In addition, we find that the ATLAS kinematic region is not sufficient to constrain the intrinsic charm contribution in protons using the $W^\mp D^{(*)\pm}$ events. Finally, we discuss the feasibility of measuring $W^\mp D^{(*)\pm}$ production in proton-lead collisions.

Speaker: Ville Alanko (University of Jyväskylä)

DIS2026_presentation_Alanko.pdf

09:00 → 10:45 WG3 Electro-weak physics/higgs/top and BSM: Precision Measurements

Conveners: Ken Mimasu (University of Southampton), Menglin Xu

09:00 Z-plus-jet Production with JETHAD-DYnamis: Angular Structure, Polarization, and Fixed-Order Matching (17'+3')

Recent studies of inclusive Higgs rates at N$^3$LO have shown that high-energy resummation effects can reach the 10\% level, reinforcing the idea that electroweak observables from LHC to FCC energies are increasingly shaped by high-energy QCD dynamics. Here we present the first high-energy-resummed predictions for Drell–Yan plus jet production, providing rapidity and transverse-momentum spectra for $Z/\gamma^*$ bosons. Our NLO calculation is matched to next-to-leading energy-logarithmic accuracy (NLL/NLO) and complemented by a new JETHAD-DYnamis–POWHEG matching strategy that incorporates polarization, angular dynamics, and realistic lepton-level kinematics. To our knowledge, this is the first implementation of high-energy resummation for rapidity-separated $Z$-boson final states. The framework improves predictions for key electroweak precision observables, directly relevant to current LHC analyses and to the High-Luminosity LHC, where percent-level control of Drell–Yan distributions is required.

Speaker: Dr Francesco Giovanni Celiberto (UAH Madrid)

talk_DIS_2026_Celiberto_Z-jet_NLL-NLO.pdf

09:20 Electroweak corrections and theoretical uncertainties in the weak mixing angle determination at the LHC and HL-LHC (17'+3')

The physics program of the LHC and the High-Luminosity LHC (HL-LHC) demands increasingly precise theoretical predictions. This is particularly crucial for measurements relying on template fit methods, where Monte Carlo event generators are used to produce event samples as a function of the parameter of interest, and the physical observable is extracted by fitting these templates to the data. In this approach, theoretical uncertainties in the Monte Carlo predictions translate directly into theoretical systematic uncertainties in the final measurement.

A prime example is the determination of the effective weak mixing angle from the forward-backward asymmetry in neutral-current Drell-Yan processes. In this contribution, we analyze specific electroweak theoretical uncertainties affecting the extraction of the weak mixing angle, extending the analysis from the Z-pole up to the TeV scale. We focus in particular on the impact of weak corrections beyond NLO and on the role of the electroweak input parameter scheme. We investigate both parametric uncertainties and those arising from technical details of the calculation, such as the treatment of resonances. The results presented are obtained using the latest release of the Z_ew-BMNNPV generator within the POWHEG BOX framework.

Speaker: Mauro Chiesa (Istituto Nazionale di Fisica Nucleare)

chiesa_dis2026.pdf

09:40 Improved extraction of the weak mixing angle from recent CMS forward-backward asymmetry measurements at 13 TeV with additional PDF constraints from W and Z measurements (17'+3')

We present an improved extraction of the effective leptonic weak mixing angle, $\sin^2\theta^\ell_{\mathrm{eff}}$, based on the published CMS measurement of the forward–backward asymmetry ($A_{\rm FB}$) in Drell–Yan dilepton production at a center-of-mass energy of 13 TeV. The published CMS extraction already reduces parton distribution function (PDF) uncertainties by profiling with the dilepton mass dependence of $A_{\rm FB}$, yet the total uncertainty remains dominated by PDFs. We further reduce the PDF uncertainty by extending the profiling to include additional CMS measurements of the $W$-boson charge asymmetry and the $W/Z$ fiducial cross-section ratios. This extended profiling yields a substantially reduced total uncertainty, resulting in , $\sin^2\theta^\ell_{\mathrm{eff}}$ = 0.23156$\pm$0.00024, which is in excellent agreement with the Standard Model prediction of 0.23161$\pm$0.00004 and constitutes the most precise single determination of $\sin^2\theta^\ell_{\mathrm{eff}}$ to date. In the profiling process with the CMS 13 TeV measurements of $A_{\rm FB}$, $W$-boson charge asymmetry and the $W/Z$ fiducial cross-section ratio we also obtain improved determination of Parton Distribution Functions.

Speaker: Dr Hyon-San Seo (University of Rochester)

260506DIS_Hyon.pdf

10:00 Towards two-loop EW corrections to the Drell-Yan process (17'+3')

In the context of the precision physics programme at the HL-LHC and the FCC-ee, electroweak corrections will play a central role. In this talk, I will discuss recent developments in the computation of two-loop electroweak amplitudes to lepton-pair production. First, I will present the ultraviolet-renormalised and infrared-subtracted finite remainder of the two-loop amplitude in quantum electrodynamics. Then, I will discuss the state of the art for extending our computational framework to the full electroweak Standard Model.

Speaker: Simone Devoto (University of Ghent)

DIS26_Devoto.pdf

10:20 $\gamma Z$ Box at Low Energy (8')

We calculate the 1-loop $\gamma Z$ box-graph correction to electron-quark scattering at low energy and low momentum transfer. Both electron and quark masses are kept non-zero. From our result, we extract coupling constants for the low-energy effective Lagrangian with parity-violating 4-fermion interaction terms. We study the zero-mass limits and show that a non-zero electron mass is sufficient to obtain finite, well-defined couplings which are insensitive to a hadronic mass cutoff. We finally discuss the impact of our results on the determination of the weak charge of the proton from polarized electron-proton scattering.

Speaker: Balma Duch (Institut de Física d'Altes Energies (IFAE))

gZboxLowEnergy_DIS26.pdf

09:00 → 10:45 WG4 QCD with Heavy flavours and Hadronic Final States

09:00 NLO Corrections to Exclusive Heavy-Quarkonium Electroproduction in pQCD

We perform various phenomenological studies of exclusive heavy-quarkonium electroproduction in $ep$ collisions that are relevant for both the existing measurements from HERA and the forthcoming Electron-Ion Collider (EIC). We provide quantitative predictions at next-to-leading order (NLO) in perturbative QCD (pQCD) for various observables accessible at HERA for both $J/\psi$ and $\Upsilon$ electroproduction that serve as valuable benchmarks across a broad range of photon virtualities $Q^2$ and $\gamma^*p$ centre-of-mass energies. We then discuss how the forthcoming EIC will open a new era of precision physics in this sector and end by advocating the need for a dedicated and systematic resummation framework for $J/\psi$ electroproduction at large $Q^2$.

Speaker: Chris Flett (CP3, UCLouvain)

DIS26_FLETT.pdf

09:20 Study of $\chi_{b1,2}(2P)\to\omega\Upsilon(1{\mathrm{S}})$ transitions in $\Upsilon(3{\mathrm{S}})\to \gamma \chi_{b1,2}(2P)$ decays at BABAR

Results are presented on $\chi_{b1,2}(2P)\to\omega\Upsilon(1{\mathrm{S}})$ transitions from $e^+e^−\to\Upsilon(3{\mathrm{S}})\to \gamma \chi_{b1,2}(2P)$ decays. The data were collected with the $BABAR$ detector at the PEP-II asymmetric-energy $e^+e^−$ collider at SLAC. The integrated luminosity of the data sample is 28.0 $fb^{−1}$, corresponding to $121.3\times 10^6$ $\Upsilon(3{\mathrm{S}})$ decays. Signals of $\chi_{b1,2}(2P)\to\omega\Upsilon(1{\mathrm{S}})$ are observed over a negligible background. Improved precision measurements of branching fractions are obtained. First measurements of the $\chi_{b1,2}(2P)$ angular distributions are performed. No evidence is found for the presence of a $\chi_{b0}(2P)\to\omega\Upsilon(1{\mathrm{S}})$ decay mode.

Speaker: Antimo Palano (Istituto Nazionale di Fisica Nucleare)

palano_dis26.pdf

09:40 Internal structure of exotic hadron candidate $f_0$(980) by using fragmentation functions

In recent years, there are experimental reports on exotic-hadron candidates, which have different quark configurations from ordinary $q\bar q$ and $qqq$ constituents. However, it is not easy to confirm their exotic nature from global observables such as masses, spins, parities, and decay widths. At high energies, internal quark and gluon configurations could become more apparent because hadrons should be described by fundamental degrees of freedom of quarks and gluons in quantum chromodynamics. One of such possibilities is to use the fragmentation functions (FFs). In this work, accurate FFs of an exotic hadron candidate $f_0$(980) are determined for the first time by an global analysis of experimental data on $e^+ + e^- \to f_0 (980)+X$ with recent precise measurements of the Belle collaboration [1]. From the global analysis, we found that their second moments have a relation $M_u = M_d \ll M_s \sim M_g $ for up-quark, down-quark, strange-quark, and gluon FFs. Furthermore, the function $D_s^{f_0}(z)$ is distributed in the larger-$z$ region in comparison with the functions $D_{u}^{f_0}(z)$, $D_{d}^{f_0}(z)$, and $D_g^{f_0}(z)$. These facts support that the $f_0 (980)$ has the $s\bar s$ configuration at high energies. This is a new finding that $f_0 (980)$ should be considered mainly as the $s\bar s$ state, which is different from our usual understanding as a tetraquark (or $K\bar K$) hadron from low-energy studies.
Our results could indicate the transition of the internal configuration picture that $f_0 (980)$ looks like a $q\bar q$ state at high energies although it is described by tetra-quark or $K\bar K$ molecule state at low energies. It sheds light on a new direction in exotic hadron physics.

[1] S. Kumano, arXiv:2511.20217, submitted for publication.

Speaker: Prof. Shunzo Kumano (IMP/KEK)

Kumano-f0-FFs-DIS2026-2026-05.pdf

10:00 Pentaquarks from Multimodal Fragmentation at NLL/NLO+

We investigate the production of fully heavy pentaquark states in the high-energy limit of QCD, where multi-particle radiation and energy-logarithmic enhancements play a central role. Within this framework, we construct an updated set of multimodal collinear fragmentation functions, denoted PQ5Q1.1, which refine and extend our previous release. The new set incorporates, for the first time, a systematic assessment of perturbative missing higher-order uncertainties and of nonperturbative effects related to the heavy-quark wave function at the origin. Our multimodal approach provides a unified description of the short-distance emission mechanisms underlying both compact multicharm configurations and diquark-quark-diquark topologies. To explore high-energy phenomenology, we employ the (sym)JETHAD interface to compute NLL/NLO$^{+}$ semi-inclusive pentaquark-plus-jet rates, highlighting their behavior in forward kinematics relevant to the HL-LHC and future FCC energies. This study advances the role of exotic multiquark states as probes of energy-logarithmic dynamics, bridging high-energy resummation techniques with the emerging field of exotic spectroscopy.

Speaker: Dr Francesco Giovanni Celiberto (UAH Madrid)

talk_DIS_2026_Celiberto_PQ5Q11.pdf

10:20 TQ4Q2.0 Fragmentation Functions for Fully Heavy Tetraquark Production

We explore the fundamental mechanisms governing exotic-matter formation through the TQ4Q2.0 collinear, variable-flavor-number-scheme fragmentation functions for fully heavy tetraquarks in three quantum configurations: scalar ($0^{++}$), axial vector ($1^{+-}$), and tensor ($2^{++}$). Short-distance inputs at the initial scale are constructed within nonrelativistic QCD factorization and include all parton-initiated channels. Scale evolution is performed via the threshold-aware HF-NRevo framework. A comprehensive uncertainty analysis is carried out by consistently combining nonperturbative contributions from color-composite long-distance matrix elements (LDMEs) with perturbative heavy-flavor-fragmentation missing higher-order uncertainties (F-MHOUs). Among the accessible configurations, the axial-vector channel stands out as a particularly sensitive probe of the proton's intrinsic charm component, especially in proton-proton collisions at LHC and FCC energies. The release of the next-generation TQ4Q2.0 fragmentation set provides a robust quantitative baseline for experimental searches of fully heavy tetraquarks across an extended kinematic domain. Overall, our study advances the interplay between hadronic structure, precision QCD, and exotic spectroscopy, offering new avenues to investigate unexplored facets of QCD and potential windows onto physics beyond the Standard Model.

Speaker: Dr Francesco Giovanni Celiberto (UAH Madrid)

talk_DIS_2026_Celiberto_TQ4Q20.pdf

09:00 → 10:30 WG5 Spin and 3D-structure

Convener: Jan Matousek (Charles University, Prague)

09:00 Di-hadron fragmentation Functions beyond LO

Di-hadron Fragmentation Functions (DiFFs) represent a unique analyzing
power to access the chiral-odd transversity parton distribution in a
collinear framework. Since present extractions of transversity through
this method are performed at leading-order (LO) accuracy, improving the
precision requires extracting DiFFs beyond LO. In this talk, I will
present a new extraction of the unpolarized DiFF up to NNLO accuracy,
using both a physics-informed parametrization and a neural-network
approach. I will also discuss preliminary aspects of the NLO extraction
of the polarized chiral-odd DiFF that partners the chiral-odd transversity.

Speaker: Luca Polano (Istituto Nazionale di Fisica Nucleare)

DIS2026_LPolano.pdf

09:20 Experimental Results on Di-Hadron Production

Two hadron production in semi-inclusive deep inelastic scattering is an
important tool to probe nucleon structure and study hadronization. In
this talk, an overview of the observables accessible with dihadron
production will be given. Preliminary results from the CLAS12 experiment
at Jefferson Lab will be shown for the target spin and double spin
asymmetries from $\pi^+\pi^-$ dihadron production with an electron beam
scattering off a longitudinally polarized hydrogen in solid ammonia
(NH$_{3}$) target.

Speaker: Nilanga Wickramaarachchi (Duke University)

DIS2026_talk_Nilanga.pdf

09:40 Dependence of Transverse Single Spin Asymmetry on Number of Electromagnetic Contributors in a Jet

Transverse single spin asymmetries (TSSA) have been studied for some time to help understand proton substructure. Their study has led to new developments in the theory of nuclear structure to include not only the collinear momentum of partons but also their transverse momentum. These new frameworks, the transverse momentum dependent parton distribution functions (TMD) and the Twist-3 collinear factorization framework, need to be understood in a wide range of kinematic coverage and particle species. To this end the STAR experiment at the Relativistic Heavy Ion Collider (RHIC) spends a considerable effort to measure the TSSA of different particle species in a wide range of Bjorken-$x$ and $Q^2$. In particular, STAR has shown that the TSSA of inclusive jets reconstructed from electromagnetic showers (electromagnetic jets) in the forward pseudorapidity region are non-zero. This talk will show the dependence of the TSSA on the number of contributors in the electromagnetic jet in the pseudorapidity region of $2.6<\eta<4.2$ at $\sqrt{s}=200$~GeV and $\sqrt{s}=510$~GeV. The data shows a clear suppression of the TSSA with increasing number of contributors at both energies. It will also give an update on the analysis of TSSA of neutral pions using the STAR forward upgrade detectors at $\sqrt{s}=510$~GeV (2022 dataset) in a similar pseudorapidity range of $2.5<\eta<4$.

Speaker: David Kapukchyan

Slides_DK_DIS2026_final.pdf

10:00 Quark and gluon Sivers function in dijets at the EIC

We explore the quark and the gluon sivers function which appear in the factorization theorem of dijet production in semi-inclusive deep inelastic scattering. We revise the unpolarized TMD case and state the possibility of re-defining the resummation method, altering the treatment of the corresponding evolution kernels. Studying the two resummation schemes we find strong dependence on gluon TMD distributions and big values of the Sivers asymmetry. For a given Sivers function model, we also present the impact of its uncertainty in the sivers weighted cross-section of the process.

Speaker: Patricia Andrea Gutierrez Garcia (Universidad Complutense de Madrid)

DIS2026_Patricia_Andrea_Gutierrez_Garcia.pdf

10:10 Tensor Polarization effects in Deep Inelastic Scattering off Spin-1 Target

We investigate semi-inclusive deep inelastic scattering off a tensor-polarized spin-1 target, focusing on the production of an unpolarized hadron. The differential cross section is parametrized in terms of 23 structure functions, depending on the target spin states and the azimuthal modulations of the detected hadron. Within the transverse-momentum-dependent (TMD) factorization framework, we derive the hadronic tensor using quark–quark and quark–gluon–quark correlators up to twist-3. At tree level, 21 nonvanishing structure functions arise at leading and subleading twist, expressed as convolutions of TMD parton distribution functions and fragmentation functions. Measurements of these structure functions provide direct access to the tensor-polarized structure of spin-1 hadrons and offer insight into their internal dynamics.

Speaker: Jing Zhao (Shandong University)

2026DIS_JingZhao0506.pdf

09:00 → 10:30 WG6 Current upgrades and future experiments

Convener: Domenico Elia (Istituto Nazionale di Fisica Nucleare)

09:00 Precision (Anti)Neutrino Interaction Measurements with SAND at DUNE

DUNE is a next-generation long-baseline neutrino experiment designed to measure all parameters governing neutrino oscillations within a single experimental framework. Achieving the precision required for these measurements demands stringent control of statistical uncertainties, which will be provided by a multi-component Near Detector (ND) complex.

The System for on-Axis Neutrino Detection (SAND) is one of the detectors comprising the ND. It will be permanently located on axis, with the primary objectives of monitoring the neutrino beam and measuring the neutrino flux. In addition, precise control of the configuration, chemical composition, and mass of the (anti)neutrino targets in SAND enables high-statistics measurements of (anti)neutrino interactions on hydrogen and other nuclear targets, including argon. The hydrogen interaction sample, specifically, can be obtained through statistical subtraction, exploiting data collected with alternating plastic and pure carbon targets.

This talk presents the SAND detector design and its physics program, and describes a proof-of-concept study exploiting the statistical subtraction method.

Speaker: Federico Battisti (Istituto Nazionale di Fisica Nucleare)

DIS26_Battisti.pdf

09:20 Ongoing Development in a Proximity-Focusing RICH Detector for ePIC at the Electron-Ion Collider

The Electron–Ion Collider at Brookhaven National Laboratory (BNL) will enable precision studies of the strong interaction in nucleons and nuclei. Its general-purpose detector, ePIC, is designed to support a broad physics program, which relies on robust particle identification capabilities. In the electron-going endcap, a proximity-focusing Ring Imaging Cherenkov detector (pfRICH) provides charged-particle identification, enabling pion–kaon separation at the 3$\sigma$ level for momenta up to 7 GeV/c.

The pfRICH consists of a cylindrical vessel with aerogel tiles mounted on the upstream side serving as the Cherenkov radiator. Conical mirrors installed along the vessel walls reflect Cherenkov photons onto a photosensor plane located on the downstream side, maximizing photon collection. The baseline photosensors are High-Rate Picosecond Photon Detectors (HRPPDs) developed by Incom, which offer large-area coverage with fine pixelation, high quantum efficiency, low dark count rates, and excellent spatial and timing resolution. A magnetic field test was recently carried out at BNL to evaluate HRPPD performance in field strengths and orientations expected at the location of the pfRICH. The mirror system requires high reflectivity ($\geq$ 90 %) over the wavelength range of 300–600 nm, as well as good uniformity, to minimize photon losses and preserve detection efficiency. At BNL, dedicated mirror test stands are used to measure reflectivity and uniformity, providing feedback which is used to optimize the mirror production procedure.

This talk will present the pfRICH detector design, mirror production and reflectivity characterization studies, and preliminary results from the first HRPPD magnetic-field test campaign at BNL.

Speaker: Jihee Kim (Brookhaven National Laboratory)

dis2026_JKIM_20260506_final.pdf

09:40 A Straw Tracker for the FCC-ee Experiments

The Future Circular electron–positron Collider (FCC-ee) will operate as a high-luminosity circular electron–positron collider, providing precise measurements of the Z, W, and Higgs bosons, as well as the top quark. To fully exploit this environment, the inner tracker must reconstruct charged-particle trajectories with high precision across a wide momentum range while keeping the material budget low to limit multiple scattering. Furthermore, the tracker needs to provide robust particle identification capabilities to distinguish among different charged particles.

We propose a straw tracker for the inner tracker of FCC-ee experiments, such as ALLEGRO. Combined with a high-resolution pixel vertex detector and an outer silicon strip tracker, it provides O(100) precise position measurements per track while keeping the material budget low. The design achieves a transverse momentum resolution of 0.1–0.2% at 45 GeV and an angular resolution of O(0.1 mrad). It also enables particle identification via measuring the energy loss (dE/dx) or the number of primary ionization clusters (dN/dx), allowing separation of charged hadrons across a broad momentum range from O(100 MeV) to O(40 GeV).

This presentation will cover the development of the straw tracker for the FCC-ee inner tracking system. Results from detailed simulations of its expected performance will be presented, along with measurements from cosmic muon studies and recent test-beam campaigns. These studies demonstrate the feasibility of the design and highlight its potential to provide precise tracking and particle identification for future FCC-ee experiments.

Speaker: Can Suslu (University of Michigan)

DIS26_StrawTracker_Can.pdf

10:00 Scintillator Strip Detector R&D for FCC-ee

The Future Circular electron-positron Collider (FCC-ee) will operate as a high-luminosity e⁺e⁻ collider for precision studies of the Z, W, Higgs bosons, and top quark. Its goals include electroweak and Higgs precision tests, searches for physics beyond the Standard Model, and providing inputs for future hadron collider programs.
A high-performance muon detector at the FCC-ee is crucial for accurately identifying and reconstructing muons produced in collisions, which are key signatures in many electroweak and Higgs studies. We propose to build a hybrid muon detector system that combines drift tubes with plastic scintillator strips. The design features one or more super-layers, each consisting of several layers of drift tubes for high-precision tracking in the bending plane (x, y). Nested above and below the tubes, orthogonally oriented layers of triangular scintillator strips provide precise z-coordinate information and fast timing signals. These strips are equipped with wavelength-shifting (WLS) fibers for efficient light collection and read out at both ends using SiPMs, enabling robust amplitude and timing measurements. The system targets a z-position resolution of 1 mm, using the strip cross-section size, the vernier effect between adjacent strips, or both. Simultaneously, the dual-end readout is designed to achieve a 200-ps resolution for time-of-flight measurements, and to determine the (x, y) position with a precision of O(1 cm) from the scintillator strips.
In this presentation, we will discuss the development of scintillator strip detectors for this application. We will present results from detailed simulations, along with experimental data obtained from recent test-beam campaigns with prototype detectors.

Speaker: Jiajin Ge (University of Michigan (US))

FCC-Muon-R&D-JiajinGe.pdf

10:20 Two-photon interactions at the LHeC

An overview of the prospects for unique studies of photon-photon interactions at LHeC will be presented. Profiting from the clean experimental environment and high luminosity at the LHeC, it will be possible to conduct stringent tests of electroweak interactions as well as meaningful searches for possible deviations from Standard Model. In particular, the cases of two-photon production of pairs of W and Z boson, tau leptons and supersymmetric particles will be discussed.

Speaker: Laurent Forthomme (AGH University Kraków)

dis-hegg_forthomme.slides.pdf

09:20 → 10:30 WG2 Small-x, diffraction and vector mesons

Convener: Cristovao Fernandes Vilela

09:20 CGC Fit to HERA DIS and Forward Hadron Production in p+p Collisions

Many experiments have provided possible hints of gluon saturation, including geometric scaling in deep inelastic scattering (DIS) at HERA, the suppression of forward particle yields in d+Au collisions relative to p+p collisions at RHIC, and the suppression of away-side peaks in di-hadron correlations at forward rapidities in proton-nucleus collisions at RHIC and the LHC. Previous studies within the Color Glass Condensate (CGC) framework have primarily focused on fits to HERA deep inelastic scattering data, using the resulting dipole amplitudes to predict hadronic observables in proton–nucleus and proton–proton collisions. A simultaneous fit of DIS and forward particle production data, and a systematic study of their interplay, has so far been absent. In this work, we focus on two processes: inclusive DIS and forward single inclusive hadron production in p+p collisions, incorporating data from HERA, RHIC, and the LHC. We solve the Balitsky-Kovchegov (BK) small-x evolution equation and perform a global fit to the combined datasets. Our analysis accounts for uncertainties in fragmentation functions and provides final uncertainties for the fitted parameters. The results demonstrate the potential of the CGC formalism to provide a universal description of these diverse processes.

Speaker: Truong My Hau Le (Jagiellonian University)

DIS_2026_presentation_Hau.pdf

09:40 Confronting CGC at NLO with HERA Structure Function data and Probing Gluon Saturation through Semi-inclusive Hadron Production at the EIC

We constrain the non-perturbative initial condition to the next-to-leading order (NLO) Balitsky-Kovchegov (BK) equation by comparing NLO DIS calculations to both the HERA total inclusive cross section and the charm quark production datasets. This global approach is done through our well-tested Bayesian framework, used in previous analysis [1] as well. The cross sections are calculated by convoluting the NLO DIS hard factors with the NLO BK equation, improved by resumming contributions enhanced by large single and double transverse logarithms. The Bayesian framework extracts the posterior distributions of the parameters that define the initial condition. We obtain an excellent description of the precise small-$x$ reduced cross section data. The resulting posterior distributions provide a rigorous way to propagate uncertainties of the initial dipole amplitude, necessary to all NLO calculations in the color glass condensate framework.

Speakers: Carlisle Casuga (University of Jyväskylä), Swaleha Mulani (University of Jyvaskyla)

DIS_2026.pdf

10:00 Probing Dense Nuclear Matter at Small-x

A central objective of the SURGE Collaboration is to investigate dense nuclear matter in the small-x kinematic region. The dipole model within the Color Glass Condensate (CGC) effective field theory provides a powerful framework for describing these phenomena. We are developing an efficient computational framework to evaluate and fit small-x data within a global analysis setting. Ongoing studies also explore the use of machine-learning models to enable rapid evaluation of BK and BFKL evolutions. This initial framework can be validated against established HERA data in preparation for future EIC measurements. The dipole model provides a valuable complement to the collinear parton model. Comparative studies can help elucidate small-x dynamics, including higher-twist contributions, parton recombination, resummation, and other collective phenomena.

Speaker: Fredrick Olness (SMU)

Olness_2026DIS.pdf

10:45 → 11:00 Coffee break - available from 10:30 to 11:30

11:00 → 13:00 WG2 Small-x, diffraction and vector mesons

Convener: Cristovao Fernandes Vilela

11:00 The DIS dipole picture cross section in exact kinematics

Predictions for the inclusive DIS total cross section at small $x$ are commonly obtained using the forward elastic scattering amplitude in the dipole picture. However, the usual dipole picture assumes an asymptotically large photon-proton center-of-mass energy $W$, such that the phase space of the produced partonic system at the unitarity cut remains unconstrained. In this work, we move away from the infinite-energy limit by implementing a finite-energy constraint that restricts the invariant mass of the produced partonic system by $W$. By explicitly integrating over the final-state phase space$-$which is possible when the optical theorem is not used$-$we derive the leading-order DIS cross section with a finite-energy constraint. We then quantify its phenomenological impact and find that, for $Q^2 = 1~\text{GeV}^2$, the constraint can modify the cross section by up to $\sim 35\%$ for charm quarks and $\sim 7\%$ for light quarks at $x = 0.01$, while the effect rapidly decreases at smaller $x$ or larger $Q^2$. Our results are relevant for precision descriptions of HERA data and for future measurements at the EIC.

Reference: Bertilsson, Lappi, Mäntysaari, Tong, https://arxiv.org/abs/2601.07302

Speaker: Magnus Bertilsson

Presentation_DIS_2026_Final-1.pdf

11:20 Geometric Scaling and Gluon Saturation at the EIC

Understanding the structure of protons and nuclei in terms of quarks and gluons is one of the key goals in science. Results from RHIC suggest the existence of a new state of matter known as gluon saturation. The idea is, at high energies, gluons, due to their self-interactions multiply rapidly; however, when their density becomes very large, recombination effects set in, leading to saturation where the gluon density stops growing. One of the objectives of the upcoming Electron-Ion Collider (EIC) in the US is to probe this saturation regime. This work presents a study of geometric scaling in eA collisions via charged particle multiplicities and their dependence on the impact parameter (b).

Geometric scaling is an elegant signature of such physics, where observables scale with a universal variable dependent on 𝑥, Q², and b. We propose to investigate geometric scaling of multiplicity distributions at the EIC using pseudodata generated with BeAGLE, a Monte Carlo event generator. BeAGLE includes an intra-nuclear cascade to model final-state interactions within the nucleus. We will use these simulations to test scaling and universality across different nuclear targets. Additionally, studying the dependence of multiplicities on impact parameter allows us to probe the spatial geometry of gluons inside the target. This work directly supports the EIC’s science goals and helps shape expectations for future experimental data.

Speaker: Rojae Mighty

DIS2026.pdf

11:40 Measurement of $\gamma \gamma \rightarrow \pi^+ \pi^-$ in Au+Au collisions at STAR using the Entanglement Enabled Spin Interference effect

In ultraperipheral collisions, the invariant mass spectrum of $\pi^+ \pi^-$ pairs is very complex due to the numerous production channels and intermediate states. The most dominant component of this spectrum is $\gamma A \rightarrow \rho^0 (770) \rightarrow \pi^+ \pi^-$ production, and the invariant mass region surrounding the $\rho^0 (770)$ is well-described with the inclusion of photonuclear ($\gamma A$) continuum and $\omega$ meson production. Two-photon processes, like those seen in electron-positron collisions, are also present in ultraperipheral collisions, but the $\gamma \gamma \rightarrow \pi^+ \pi^-$ process has not yet been measured in a nuclear environment due to its low cross section relative to the photonuclear channel. Wavefunction-level interference between the $\gamma \gamma $ and $\gamma A$ channels, referred to as Entanglement Enable Spin Interference (EESI), is expected to produce $A_{1\Delta \phi}$ and $A_{3\Delta \phi}$ signals. This represents a unique method to access the $\gamma \gamma \rightarrow \pi^+ \pi^-$ process in the complex environment of ultraperipheral collisions.

In this talk, the first measurement of EESI between photonuclear and light-by-light production of $\pi^+ \pi^-$ pairs, including the strong EESI signal associated with the $f_2(1270)$ resonance, will be presented. The EESI observables are then used to isolate $\gamma \gamma \rightarrow \pi^+ \pi^-$ in ultraperipheral $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{NN}} = 200$ GeV.

Speaker: Samuel Corey (The Ohio State University)

scorey_DIS2026_slides_final.pdf

12:00 Exploring the frontier of high energy QCD with the LHuC

We discuss the potential of the recently proposed LH$\mu$C (anti-muon-proton collider at CERN) in exploring both the perturbative and non-perturbative aspects of QCD. With the access to an unprecedentedly low Bjorken $x$, as low as $10^{-7}$ at perturbative virtualities $Q^2\simeq1$ GeV$^2$, the LH$\mu$C will allow to study the properties of protons and nuclei in the gluon saturation regime, where the nonlinear evolution equations for parton distribution functions become indispensable. Furthermore, an access to low-$x$ at large virtualities will significantly bring down the uncertainties in co-linear PDFs and has potential for precise extraction of the strong coupling constant.

Speaker: Piotr Kotko (AGH University of Krakow)

DIS2026-Kotko.pdf

12:20 Differential Higgs production at small x

I will present new results on the inclusion of small-x resummation in the computation of the production of a Higgs boson, differential in rapidity and transverse momentum. The implementation in the HELL framework is discussed, as well as phenomenological implications for LHC and future high-energy colliders.

Speaker: Benedetta Bernardini

Bernardini_DIS2026.pdf

11:00 → 13:00 WG5 Spin and 3D-structure

Convener: Matteo Cerutti

11:00 Tensor-polarized twist-3 distribution function $f_{LT}$ of spin-1 deuteron

The spin-1 deuteron possesses tensor-polarized structure functions that have no analogue in spin-1/2 hadrons, and an experimental program at JLab is being planned to explore this unique aspect of hadronic structure. In a few GeV$^2$ region of $Q^2$, higher-twist effects may become significant. In this work [1], we showed the first quantitative evaluation of the tensor-polarized twist-3 parton distribution function $f_{LT}(x)$.

Starting from the twist-2 distribution $f_{1LL}(x)$ [2] extracted from the HERMES data on the tensor-polarized structure function $b_1$, we used a Wandzura-Wilczek-like relation [3] to estimate the twist-3 distribution $f_{LT}(x)$. Our analysis demonstrated that the resulting twist-3 distribution $f_{LT}(x)$ is comparable in magnitude to the twist-2 distribution $f_{1LL}(x)$, indicating that twist-3 effects may play a non-negligible role. Furthermore, we found that the twist-3 $f_{LT}(x)$ exhibits an oscillatory behavior in Bjorken-$x$, similar to the twist-2 $f_{1LL}(x)$, and it satisfies a Burkhardt-Cottingham-like sum rule [3], which we verified numerically. These results provide timely input for future experimental studies of spin-1 hadrons.

[1] S. Kumano and K. Kuroki, arXiv:2509.05046.
[2] S. Kumano, Phys. Rev. D 82, 017501 (2010).
[3] S. Kumano and Qin-Tao Song, JHEP 09, 141 (2021).

Speaker: Kenshi Kuroki (Institute of Modern Physics, CAS)

Talk_DIS2026_kuroki.pdf

11:20 Coherent deeply virtual Compton scattering on Helium-4 beyond leading twist approximation.

Coherent hard exclusive reactions on light nuclei offer access to their quark and gluon structure and provide a framework for three-dimensional nuclear tomography. We analyze deeply virtual Compton scattering on a helium-4 target, including leading-twist contributions as well as kinematical twist-3 and twist-4 effects. We present numerical estimates of cross sections and asymmetries for kinematic regimes relevant to JLab experiments and the forthcoming Electron-Ion Collider.

Speaker: Jakub Wagner (National Centre for Nuclear Research)

Wagner_DIS2026.pdf

11:40 Resummed Power Corrections in Nuclear DVCS

We present a systematic study of nuclear-enhanced power corrections in deeply virtual Compton scattering (DVCS) on nuclear targets, extending techniques developed for inclusive deep inelastic scattering to exclusive processes. Using a light-cone operator product expansion and the method of regions, we identify coherent final-state interactions of the struck quark as the dominant source of higher-twist nuclear modifications. These contributions can be resummed to all orders, leading to compact expressions for the DVCS amplitude characterized by a single nonperturbative scale and enhanced by nuclear size effects. Our formalism provides a controlled framework for quantifying nuclear modifications to generalized parton distributions at small momentum transfer and moderate photon virtuality. The results establish a direct theoretical connection between inclusive DIS dynamics and exclusive nuclear observables, with important implications for three-dimensional imaging of nuclei at future facilities such as the Electron–Ion Collider.

Speaker: Ivan Vitev (LANL)

IVitevDVCS2026fin.pdf

12:00 Accessing GPDs via Deeply Virtual Exclusive Processes at CLAS12

Since 2018, the CLAS12 experiment located in Hall B at Jefferson National Laboratory, Newport News, VA, USA has collected electron scattering data over a broad kinematic range at beam energies up to 10.6 GeV.  A collaboration of CLAS12 physicists from Jefferson Lab, MIT, and Tel Aviv University is developing several analyses of CLAS12 data aimed at extracting new information on the quark and gluon structure of the proton in the valence region via determination of cross sections for deeply virtual exclusive processes, where the additional particle produced in the final state, e.g. $\gamma$, $\pi^0$, $\phi$, is detected in coincidence with the scattered electron and recoil proton.  Such cross sections are known to be sensitive to non-forward, nonlocal structure characterized by Generalized Parton Distribution Functions (GPDs) and gravitational form factors.  The cross sections for different exclusive final states are measured at several beam energies and presented as functions differential in kinematic variables $Q^2$, $x_B$, $t$, and $\phi$.  Current results will be reported and the future perspective presented.

Speaker: Story Frantzen (Massachusetts Institute of Technology)

DIS2026_Frantzen.pdf

12:20 First measurement of the DVCS beam spin asymmetry in the Sullivan process

Deeply Virtual Compton Scattering (DVCS) is a powerful tool to investigate the internal structure of hadrons in terms of Generalized Parton Distributions (GPDs). The Sullivan process, involving the exchange of a virtual pion from the proton’s meson cloud, offers a unique opportunity to access the three-dimensional structure of the pion at high energies. Since the pion plays a central role in QCD dynamics, being the lightest hadron and the Goldstone boson associated with chiral symmetry breaking, understanding its structure is of fundamental importance for our understanding of hadronic matter.

This work aims at measuring, for the first time, the DVCS beam spin asymmetry (BSA) in the Sullivan process, using data collected with the CLAS12 experiment at Jefferson Lab with a 10.6 GeV electron beam on a proton target. These preliminary results demonstrate the feasibility of this novel measurement and provide an important first step toward a quantitative understanding of the Sullivan process, validating this approach as a tool to probe the pion’s internal dynamics. This first measurement paves the way for an exploration of the pion structure through its GPDs, and sets the stage for future studies at Jefferson Lab and at the upcoming Electron-Ion Collider.

Speaker: Elouan Ferrand

SullivanDVCS_Ferrand_DIS2026.pdf

12:40 Probing Nucleon GPDs at CLAS12: Neutron DVCS and $\Lambda$ Transverse Polarization

Understanding the internal structure of nucleons remains a fundamental challenge in hadronic physics. Generalized Parton Distributions (GPDs) provide a universal framework to describe this structure by correlating the partons' longitudinal momentum with their transverse spatial distribution. This 3D imaging gives access to partonic angular momentum and helps address the long-standing proton spin puzzle by constraining orbital contributions to the total nucleon spin.
Deeply Virtual Compton Scattering (DVCS) is one of the cleanest channels to access GPDs. This talk will detail the extraction of the neutron DVCS cross sections from the CLAS12 experiment at Jefferson Lab, with the electron beam about 10.4 GeV scattering off a liquid deuterium target. Preliminary cross-section results will be presented, providing valuable inputs for GPD models.
Furthermore, the exclusive production of $K^+\Lambda$ pairs offers sensitivity to specific GPD components that are suppressed in DVCS. This talk will also discuss an ongoing study of $\Lambda$ hyperon transverse polarization with a longitudinally polarized NH3 target at CLAS12, which probes chiral-odd GPDs and provides a complementary perspective on the nucleon's 3D structure.

Speaker: Li XU (Brookhaven National Laboratory)

CLAS12_nDVCS_LamPolar_LiXU.pdf

11:00 → 12:45 WG6 Current upgrades and future experiments

Convener: Boxing Gou (Institute of Modern Physics, CAS)

11:00 Developments and Performance of ATLAS Electron and Photon Triggers in Run 3

A number of flagship analyses in the ATLAS experiment rely on electron and photon triggers to efficiently record events of interest. During Run 3, these triggers have undergone significant developments, including the integration of advanced machine learning techniques, to achieve high efficiency while controlling background rates and operating within the constraints of the trigger hardware. This contribution presents the design, optimisation, deployment, and validation of the ATLAS Run 3 electron and photon triggers, and discusses their impact on key physics analyses.

Speaker: Timoty Duong (CNRS - LAPP)

DIS2026. The ATLAS Trigger System.pdf

11:20 The upgrade of the ATLAS Trigger and Data Acquisition system for the High Luminosity LHC

The ATLAS experiment at CERN is constructing upgraded system for the "High Luminosity LHC", with collisions due to start in 2030. In order to deliver an order of magnitude more data than previous LHC runs, 14 TeV protons will collide with an instantaneous luminosity of up to 7.5 x 10e34 cm^-2s^-1, resulting in much higher pileup and data rates than the current experiment was designed to handle. While this is essential to realise the physics programme, it presents a huge challenge for the detector, trigger, data acquisition and computing. The detector upgrades themselves also present new requirements and opportunities for the trigger and data acquisition system. The design of the TDAQ upgrade comprises: a hardware-based low-latency real-time Trigger operating at 40 MHz, Data Acquisition which combines custom readout with commodity hardware and networking to deal with 4.6 TB/s input, and an Event Filter running at 1 MHz which combines offline-like algorithms on a large commodity compute service with the potential to be augmented by commercial accelerators . Commodity servers and networks are used as far as possible, with custom ATCA boards, high speed links and powerful FPGAs deployed in the low-latency parts of the system. Offline-style clustering and jet-finding in FPGAs, and accelerated track reconstruction are designed to combat pileup in the Trigger and Event Filter respectively. This contribution will report recent progress on the design, technology and construction of the system. The physics motivation and expected performance will be shown for key physics processes.

Speaker: Kazuki Todome

DIS_todome.pdf

11:40 Energy recovery linacs: from PERLE to the LHeC

The development of Energy Recovery Linacs is one of the objectives of the ECFA Accelerator R&D Roadmap established in the 2021 European Strategy for Particle Physics, and in the Recommendations by the European Strategy Group for the 2026 Update [1]. In this talk we present the development of ERLs with a focus on their application to high-energy accelerators. We discuss the present status and technical challenges of ERL, from PERLE at IJCLab, Orsay, to the proposal of the LHeC as a project to bridge the HL-LHC to the next flagship at CERN, for which the successful demonstration of high-current multi-turn ERL at PERLE is an essential milestone. We will also highlight the important synergies between PERLE and FCC in the SRF domain.
[1] The European Strategy for Particle Physics: 2026 Update - Recommendations by the European Strategy Group, https://cds.cern.ch/record/2950671/files/CERN-ESU-2025-002.pdf?version=1.

Speaker: Achille Stocchi

PERLE - BOLOGNA - DIS - NEW.pdf

PERLE - BOLOGNA - DIS - NEW.pptx

12:00 Design and development status of Silicon Vertex Tracker for ePIC experiment

At the BNL Electron Ion Collider, the ePIC experiment will investigate a broad and rich QCD and Nucleon physics program, requiring novel and high-performance detectors. An example is its Silicon Vertex Tracker (SVT). It has several innovative aspects, starting from sensors to the mechanics. It consists of three sub-systems: Inner Barrel (IB), Outer Barrel (OB), and Disks. The common innovative features are sensor technology, consisting of radiation-hardened TPSCo 65 nm CMOS imaging Monolithic Active Pixel sensor chips, ultra-light mechanical structures, and air cooling system.
In the IB, bent wafer-sized chips will directly cover the cylindrical tracking surfaces. Their mechanical bending occurs during the assembly of the detector layers, outside the TPSCo company. Even if the challenges of the assembly procedure are faced in synergy with the ALICE ITS3 project, the larger radii of the IB cylinders drive dedicated R&D solutions for the SVT sub-system.
The OB and Disks will cover larger areas, which led to different segmentations and layouts of power supply and data transmission. Therefore, the design of OB and Disks sensors slightly differs from the IB and ALICE ITS3 sensors.
Several studies are in advanced status to finalise the detector design, using simulation frameworks or preliminary mock-ups. They will be reported and discussed in this contribution, after describing the most recent design of SVT.

Speaker: Domenico Colella (INFN and University of Bari)

DIS_Colella_SVT_20260506.pdf

12:20 Quantum Tomography for Collider Physics: From Data-Driven Foundations to AI-Enhanced Methods

We present quantum tomography (QT) as a new framework for uncovering the internal structure of hadrons in high-energy collisions. Inspired by techniques from quantum state reconstruction, QT provides a data-driven approach for reconstructing higher-dimensional features of hadronic structure directly from lower-dimensional experimental data, without reliance on specific models.

We illustrate this framework through applications to ultra-peripheral collisions (UPCs) and processes at the Electron-Ion Collider (EIC), showing how QT can access 3D spatial and momentum distributions in exclusive and semi-inclusive reactions.

Building on these foundations and examples in DIS-related measurements, we introduce AI-driven extensions enabling it to tackle the large, complex datasets emerging from modern facilities like the LHC and EIC.

This work opens a new pathway for fundamental physics to uncover the hidden multidimensional structure of matter directly from experimental measurements.

Speaker: Prof. Daniel Tapia Takaki (The University of Kansas)

DTT - DIS 2026.pdf

12:28 The ATLAS Forward Proton Time-of-Flight Detector System

The Time-of-Flight (ToF) detectors in the ATLAS Forward Proton (AFP) system are used to measure the primary vertex z-position of the pp -> pXp processes using the arrival times of the two intact final state protons. During LHC Long Shutdown 2, the ToF detector underwent major upgrades in electronics, optics, and mechanics, expected to provide a substantial improvement in detection efficiency. Detection efficiencies and timing resolutions using low, moderate and high pile-up data collected during LHC Run 3 are presented. The efficiency dependence on the event rate will be shown. The resolutions of the two ToF detectors of around 30 ps were measured, which corresponds to the expected precision of 9.0 ± 0.1 mm for the vertex reconstruction. Finally, the improvements to restore efficiencies at high rates will be discussed.

Speaker: Viktoriia Lysenko (Czech Technical University in Prague (CZ))

DIS_26_05_06_ToF_Lys.pdf

11:15 → 13:00 WG3 Electro-weak physics/higgs/top and BSM: Higgs Physics

Conveners: René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

11:15 LHCb Run 3 low-mass Drell-Yan and EW measurements (22'+3')

The measurement of Drell-Yan dilepton production at hadron colliders is a key channel to constrain the partonic content of hadrons. There exists no measurement at masses below 10 GeV/c and low transverse momentum at hadron colliders due to the dominating background from semileptonic decays of charm and beauty hadrons. The SemiCharmTag algorithm is presented to increase the signal-to-background ratio and to retrieve unbiased properties of leptons from semileptonic decays of charm hadrons. The impact of the introduction of such algorithm will be discussed in the context of the Run 3 data-taking period, comparing it to previous LHCb measurements.

Speaker: Alisha Lightbody (Université Paris Saclay - CEA Saclay)

DIS2026_LIGHTBODY.pdf

11:35 Parton-shower and fixed-order QCD effects in Higgs boson production in weak-boson fusion and its decays to bottom quarks (17'+3')

I report on our recent calculations for Higgs production in weak-boson fusion with subsequent decays of the Higgs boson to bottom quarks. We take into account NNLO QCD corrections to the production and decay and also consider a parton-shower-based description for the Higgs decay. We observe large corrections to fiducial observables in the fixed-order calculation, which we trace back to mainly soft and collinear QCD radiation from the decay. We then show that a parton-shower-based calculation can help to improve the description.

Speaker: Arnd Behring (Max Planck Institute for Physics)

behring-dis2026.pdf

11:55 Higgs coupling and properties at CMS (17'+3')

The talk will cover recent measurements of Higgs cross sections and its coupling to the standard model particles. It will also describe the properties of this particle, including its mass, CP properties and polarization states of the decay products using data collected by the CMS experiment during LHC Run2 and Run3.

Speaker: Océane Poncet (The State University of New York SUNY (US))

DIS2026_Higgs_Poncet_oceane.pdf

12:15 Electroweak corrections to Higgs+jet production (17'+3')

The production of a Higgs boson in association with a high-pT jet provides a clean and sensitive channel to study the Higgs kinematics and couplings, and plays a crucial role in differential analyses at the LHC. We present the calculation of complete next-to-leading order electroweak corrections to the Higgs boson production in gg->Hg channel. We apply the method of differential equations combined with the selection of optimized master integrals to accomplish the calculation of master integrals. We consider three renormalization schemes. At leading order, the differential distributions and the total cross section show a strong dependence on the renormalization scheme. These discrepancies are considerably suppressed once electroweak corrections are taken into account. For Gmu scheme, the electroweak correction amounts to approximately 4.3% of the total cross section. Importantly, we find that the EW corrections exhibit a strong dependence on Higgs transverse momentum.

Speaker: Haitao Li (Shandong University)

haitao_HJ.pdf

12:35 Data-driven estimation of fake τ-lepton background in the H±→τν search with ATLAS Run-II data. (8')

Talk Abstract Searching for Beyond Standard Model (BSM) physics is a key objective of the ATLAS experiment at the LHC. Many BSM scenarios, such as two-Higgs-doublet models (2HDM) and the Minimal Supersymmetric Standard Model (MSSM), predict additional Higgs bosons, including a charged Higgs boson (H±). In these models, the decay H±→τν​ is expected to have a significant branching fraction over a wide H± mass range. A major challenge in analyses involving reconstructed tau leptons is the estimation of backgrounds from jets misidentified as hadronically decaying taus. To address this, a dedicated data-driven fake factor method is employed. The talk presents the fake tau background estimation procedure in the context of the H±→τν​ search, along with the latest results from the full Run-II (2015–2018) dataset of √s=13 TeV proton–proton collisions recorded by the ATLAS detector. The presented constraints are the most stringent limits to date on charged Higgs boson production in the H±→τν channel.

Speaker: Monika Juzek (Institute of Nuclear Physics Polish Academy of Sciences)

DIS_Conference_Juzek.pdf

11:15 → 13:00 WG4 QCD with Heavy flavours and Hadronic Final States

11:15 Multiplicative NLO matching in DIS with Pythia 8

We present a multiplicative matching scheme for neutral-current deep inelastic scattering implemented in the latest version of the Pythia 8 event generator. The method reweigths leading-order events to achieve next-to-leading-order (NLO) accuracy for inclusive observables. We compute NLO weights fully differential in Born variables and use matrix-element corrections to produce correct real-emission probabilities in the parton shower. The massless NLO structure functions are implemented with full interference between a photon and a Z boson with an option to consider each component separately. This is the first process that can be generated at NLO accuracy internally in Pythia without resorting to external tools for matrix-element generation. We validate the method against similar implementations in Sherpa and Powheg event generators, compare to cross sections measured at the HERA collider and discuss implications to the future Electron-Ion Collider.

Speakers: Ilkka Helenius (University of Jyväskylä), Joni Laulainen (University of Jyväskylä)

IH-DIS-2026.pdf

11:35 New techniques for reconstructing and calibrating hadronic objects with ATLAS

The precision and reach of physics analyses at the LHC is often tied to the performance of hadronic object reconstruction & calibration, with any incremental gains in understanding & reduced uncertainties being impactful on ATLAS results. Recent refinements to the reconstruction and calibration procedures for jets & missing energy by the ATLAS collaboration has resulted in reduced uncertainties, improved pileup stability and overall performance gains. In this contribution, highlights of these developments will be presented.

Speaker: Kiran Farman

DIS2026_v4.pdf

11:55 Recent Jet Substructure Measurements at LHCb

Jet substructure measurements provide precision tests of Quantum Chromodynamics through detailed studies of parton shower evolution and hadronization in vacuum. The LHCb experiment exploits its unique forward acceptance and excellent tracking to extend these measurements to low and moderate jet transverse momentum in 𝑝𝑝 collisions at 𝑠√=13 TeV. Recent results include the first measurement of the Lund jet plane for beauty-initiated jets, compared to light-quark–enriched jets, revealing clear mass-dependent modifications to QCD radiation patterns consistent with heavy-quark dynamics and the QCD dead-cone effect. In parallel, LHCb has performed the first measurement of the b-jet mass using a theoretically well-defined flavour-tagging scheme, providing a high-precision test of perturbative QCD and sensitivity to gluon-splitting contributions to heavy-flavour production. These measurements are complemented by studies of hadron production and energy-flow observables within jets, offering a comprehensive view of jet fragmentation at forward rapidity. Together, these results provide stringent constraints on parton shower models and deepen our understanding of QCD jet formation in previously unexplored regions of phase space.

Speaker: Lorenzo Sestini (Istituto Nazionale di Fisica Nucleare)

DIS2026_jet_substructure_LHCb_v2.pdf

12:15 Measurement of transverse polarization of Λ / Λ¯ inside jets in unpolarized p+p and p+Au collisions at RHIC

The transverse polarization of $\Lambda$/$\bar{\Lambda}$ in unpolarized hadron-hadron reactions, first observed decades ago, is still not fully understood. The polarizing fragmentation functions (pFFs), which give rise to the $\Lambda$/$\bar{\Lambda}$ polarization, can be investigated by measuring the $\Lambda$/$\bar{\Lambda}$ transverse polarization inside jets. In this contribution, we will present the measurements of $\Lambda$/$\bar{\Lambda}$ polarization within jets in $p$+$p$ collisions at $\sqrt{s} =$ 200 and 510 GeV, as well as in $p$+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV collected by the STAR experiment at RHIC. Measurements at different collision energies in $p$+$p$ collisions can probe the energy scale dependence of the polarization, while comparisons between $p$+$p$ and $p$+Au collisions explore possible cold nuclear medium effects. These measurements provide a critical test of the universality of pFFs and offer new insights into the mechanisms behind the $\Lambda$/$\bar{\Lambda}$ polarization.

Speaker: Xiaohui Liu (Shandong University)

DIS2026_XiaohuiLiu.pdf

12:35 Recent jet measurements in CMS

Measurements of jet production in proton-proton collisions at the LHC are crucial for precise tests of QCD, improving the understanding of the proton structure and are important tools for searches for physics beyond the standard model. We present the most recent set of jet measurements performed using CMS data and compare them to various theoretical predictions.

Speaker: Mr Leyun Gao (Peking University)

report.pdf

11:30 → 12:50 WG1 Structure functions and parton densities

Convener: Thomas Gehrmann (Universität Zürich)

11:30 NPC fragmentation functions and calculations of SIDIS at N3LO in QCD

In this talk I will report recent progress on the NPC analysis of fragmentation functions of light charged hadron, including a next-to-next-to-leading order (NNLO) analysis, its implication for strange-quark PDFs, as well as a comparison to non-perturbative models. Furthermore, I will briefly introduce our recent calculations on SIDIS at N3LO in QCD.

Speaker: Jun Gao

dis26JG.pdf

11:50 COMPASS colinear multiplicities on proton and deuteron targets

COMPASS has recently published results on pion and kaon colinear multiplicities measured on a proton target in Physical Review D 112 (2025) 012002. One of the key improvements over previous COMPASS analyses is a more accurate treatment of radiative corrections using the DJANGOH Monte Carlo generator. Compared to the previously used method, relative differences up to 10% are observed at the level of the multiplicities.
Due to the non-negligible impact of these corrections, the COMPASS Collaboration decided to update the deuteron-target multiplicity data, originally published in 2016, using the new radiative-correction procedure. The updated results have been submitted for publication in Physics Letters B.

At the conference, we shall present a final set of multiplicity values for both deuteron and proton targets. These results will serve as important input for global fits of fragmentation functions, as well as for combined fits of fragmentation functions and parton distribution functions.

Speaker: Marcin Stolarski (NCBJ)

dis_26.pdf

12:10 Hadronization Dynamics in the Nuclear Medium: Preliminary Insights from the CLAS12 RGE Experiment at Jefferson Lab

Studying hadronization - the process by which quarks and gluons transition into hadrons -is fundamental to understanding the strong interaction dynamics within quantum chromodynamics (QCD). Using the CLAS12 detector at Jefferson Lab, the Run Group E (RGE) experiment offers unprecedented insights into hadronization in the nuclear medium. This talk will present preliminary results from the experiment, focusing on the behavior of hadrons produced in 11-GeV electron-nucleus scattering. The experiment employs various nuclear targets, enabling a comparative study of medium effects on hadron formation and propagation. By analyzing observables such as hadron multiplicity ratios, transverse momentum broadening, and energy loss, we explore the interaction of quarks and hadrons with the nuclear environment. These measurements provide critical data for understanding color confinement and hadronization timescales, shedding light on QCD processes in dense media. The talk will also highlight the innovative Double-Target system developed for RGE, which facilitates rapid target switching to enhance data collection efficiency.

Speaker: Prof. Hayk Hakobyan (Universidad Tecnica Federico Santa Maria)

Bologna_May_2026.pdf

12:30 Towards NNFF2.0

I present the current status of the NNFF2.0 project, aimed at a next-generation determination of fragmentation functions within the NNPDF framework. The analysis incorporates recent NNLO calculations for inclusive hadron production in deep-inelastic scattering and hadron–hadron collisions, and exploits exact NNLO theory predictions rather than K-factor approximations. On the methodological side, the fit is performed using an optimized neural-network architecture determined through a systematic hyperparameter scan. I discuss the associated software developments, including an improved interpolation-grid infrastructure and a new tool for the efficient computation of theory predictions required in the fit. Using existing FF sets as benchmarks, I assess the phenomenological impact of these theoretical and methodological improvements and outline their implications for the forthcoming NNFF2.0 release.

Speaker: Tanishq Sharma (Michigan State University)

Towards NNFF2_TS.pdf

13:00 → 14:30 Lunch break

14:30 → 15:50 WG1 Structure functions and parton densities

Convener: Pavel Nadolsky (Michigan State University)

14:30 Precise predictions for semi-Inclusive DIS

The production of identified hadrons in lepton-nucleon scattering (semi-inclusive deep inelastic scattering, SIDIS) allows for detailed analyses of parton distributions and fragmentation functions.
For polarised nucleons, the spin structure of the nucleon target can be proved to a more detailed level than through fully inclusive processes.
We present our calculations of the full set of next-to-next-to leading order (NNLO) QCD corrections to polarised and unpolarised neutral and charged current SIDIS coefficient functions.
We study the numerical impact of our results with a focus on the kinematical settings of the future Electron-Ion Collider (EIC).
We further highlight the impact that our results will have on the extraction of fragmentation functions from so-far ignored neutrino-induced SIDIS data.
Our results enable for the first time a consistent treatment of charged and neutral current induced hadron fragmentation processes in DIS at NNLO in QCD.

Speaker: Thomas Gehrmann (Universität Zürich)

Gehrmann_DIS2026.pdf

14:50 Taking dimuon production in DIS to NNLO precision

Dimuon production in neutrino-nucleus collisions remains an important constraint of strangeness in nucleons. In most global analyses of proton and nuclear parton distribution functions, dimuon production is computed by assuming factorization to inclusive charm DIS production, an assumption that is valid only at leading order in the fixed-flavor number scheme. Our approach based on semi-inclusive DIS foregoes this assumption. We present an update to our framework [1, 2], where we take the SIDIS calculation to NNLO precision, the forefront in nuclear PDF analyses. We find that the NNLO calculation decreases the scale uncertainty in comparison to our previous NLO calculation indicating good perturbative convergence. We also see that the cross section values are modified by up to 10-20% relative to the NLO calculation in a wide kinematical range, including at small and moderate values of momentum transfer, and in the valence region and smaller values of Björken-$x$.

References:
[1] I. Helenius, H. Paukkunen and S. Yrjänheikki: Dimuons from neutrino-nucleus collisions in the semi-inclusive DIS approach, JHEP 09 (2024) 043 [arXiv:2405.12677]
[2] I. Helenius, H. Paukkunen and S. Yrjänheikki: Improving the description of dimuon production in neutrino-nucleus collisions using the SACOT-$\chi$ scheme, JHEP 01 (2026) 112 [arXiv:2506.09492]

Speaker: Sami Yrjänheikki (University of Jyväskylä)

yrjanheikki_dis2026.pdf

15:10 Electroproduction structure function F2 in the low Q2, low x region - an update

The proton structure function $F_2$ in the low $Q^2$, low $x$ region
is constructed and analysed using the generalised vector meson
dominance representation with the large $Q^2$ spectral function
calculated from the analytic continuation of the parton model
structure function. This is an update of the work published in
Z. Phys.{\bf C}43 (1989) 251 and Phys. Lett. {\bf B} 295 (1992) 263, with
various modern parton parametrisations. Possible effects of the
large $Q^2$ scaling violation on the low $Q^2$ part of the $F_2$
are investigated. Predictions of the model are compared with
available electroproduction measurements. The analysis permits
understanding of the transition from the perturbative to nonperturbative
regions (including photoproduction) and thus of the experimental
results. It may also be of a high practical value in radiative
correction procedures to be applied in extraction of structure
functions from the data e.g. in the future Electron-Ion Collider.

Speaker: Barbara Badelek (University of Warsaw)

badelek_dis2026.pdf

15:30 New results on small-x resummation for splitting functions

In the context of an ongoing project that aims to include the resummation of small x logarithms in the determination of the parton distributions of a muon, relevant for the description of scattering processes at a future muon collider, we have made significant progress in the resummation of splitting functions. We will describe some technical details and present new results.

Speaker: Marco Bonvini (Istituto Nazionale di Fisica Nucleare)

bonvini_DIS2026.pdf

14:30 → 16:00 WG2 Small-x, diffraction and vector mesons

Convener: Jani Penttala (UCLA)

14:30 Rotating the Color Glass Condensate: Stabilizing High-Energy Evolution at NLO

High-energy QCD evolution beyond leading order suffers from instabilities driven by large collinear logarithms. We present a framework, consistent with the standard high-energy operator product expansion (OPE), that restores perturbative stability order by order. The method involves a change of basis in the space of high-energy operators, which modifies both the evolution kernel and the coefficient functions while leaving physical observables invariant. Within this factorization scheme, we derive a next-to-leading-order renormalization-group equation whose numerical solution exhibits stable evolution up to large rapidities, thereby establishing a solid foundation for precision studies of gluon saturation at current and future colliders.

Speaker: Piotr Korcyl (Jagiellonian University)

DIS2026_Piotr_Korcyl_talk.pdf

14:50 Rapidity regulators for the CGC: DIS structure functions at low x at NLO

In recent years, numerous studies have aimed at improving the precision of the theoretical description of the nonlinear QCD regime of gluon saturation in high-energy collisions, in order to match the precision of the data coming from the LHC and the future EIC. In particular, NLO QCD corrections have been calculated for many high-energy processes sensitive to gluon saturation.

In most of such NLO calculations, the chosen regularization procedure is dimensional regularization for the transverse integrals complemented by a naive cut-off for the light-cone momentum k^+ integrals. Although convenient in that context, this regularization procedure has disadvantages. On the one hand, it does not allow us to disentangle soft and rapidity divergences, which are then both regulated by the cut-off. On the other hand, it complicates the comparison with results obtained in other formalisms for QCD valid in different kinematical regimes, for example collinear or TMD factorizations, which typically use other regularization schemes.

As an alternative, we discuss how to implement in these NLO gluon saturation calculations various rapidity regulators similar to the ones used by the TMD or SCET communities. As a first application and consistency check, we revisit the calculation of the NLO corrections to the DIS structure function at low x in the dipole factorization approach, now with these rapidity regulators together with dimensional regularization. When combining the results from all diagrams, we find as expected that the UV divergences are canceling each other, as well as the soft divergences. The only surviving divergence is the rapidity divergence associated with the Balitsky-Kovchegov evolution of the dipole operator.

Among the finite NLO corrections to the structure functions, the ones which are found to depend on the rapidity regularization scheme are compatible with the expected scheme dependence concerning the choice of evolution variable for the BK equation. This suggests that choosing one of the three rapidity regulators we propose amounts to choosing the precise evolution variable in the definition of the low x evolution: light-cone momentum k^+ or k^- or rapidity.

Speaker: Guillaume Beuf (National Centre for Nuclear Research (NCBJ), Warsaw)

GBeuf_DIS_2026.pdf

15:10 Recent advances to the solution of the next-to-leading order Balitsky-Kovchegov equation

In this talk a solution of the target-rapidity Balitsky-Kovchegov (BK) equation at the next-to-leading order (NLO) level is presented. At first, a version of the BK equation that includes only most important collinear part of the NLO contribution is used and the solution with the complete impact-parameter dependence is shown, including the orientation of the dipole with respect to the impact-parameter vector. This solution is used to compute the structure functions of the proton and the diffractive photo- and electro-production of vector mesons off protons. The predictions agree well with HERA and LHC data, confirming that the target-rapidity Balitsky-Kovchegov equation with the full impact-parameter dependence is a viable tool to study the small Bjorken-$x$ limit of perturbative QCD at current facilities like RHIC and LHC as well as in future colliders like the EIC.
Furthermore, a version of the BK equation that includes the full NLO contribution is used and the solution with the dependence on magnitudes of the size of the dipole and of the impact parameter is shown.}

Speaker: Jan Cepila (Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering)

DIS2026_Cepila.pdf

15:30 Study of the Nc dependence of TMD’s initial condition for JIMWLK evolution

To evaluate the high-energy dependence of the dipole or transverse momentum distributions (TMDs) within the color glass condensate framework, one relies on evolution equations such as the JIMWLK equation, or its large-Nc limit the BK equation.
It has been observed that the discrepancy between solutions for the dipole from the BK equation and the JIMWLK equation is less than expected from Nc-power counting. To study this puzzling observation, we evaluate the Nc-dependence of initial condition for TMDs, in addition to the dipole, which are generated stochastically according to the MV-model for SU(Nc) with Nc = 2,3,4,5. We identify scaling properties of those distributions analytically and numerically and identify which TMDs could be used as tools to solve this puzzle.

Speaker: Florian Cougoulic (Jagiellonian University)

IC-Nc-dep.pdf

14:30 → 16:15 WG3 Electro-weak physics/higgs/top and BSM: Higgs Physics & BSM

Conveners: René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

14:30 Search for rare decay of SM Higgs to light scalars in the CMS experiment (17'+3')

A variety of searches for the SM Higgs boson decaying to a pair of light scalars are performed with p-p collisions data collected by the CMS detector. In this talk, we present recent highlights from these searches.

Speaker: Fengwangdong Zhang

higgs_aa_talk_feng.pdf

14:50 ATLAS Searches for new scalars & BSM Higgs decays (17'+3')

The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs bosons, beyond-the-Standard-Model couplings to the Higgs boson, or new particles decaying into Higgs bosons. In this talk, the latest searches in the Higgs sector by the ATLAS experiment are reported.

Speaker: Monica Verducci (Istituto Nazionale di Fisica Nucleare)

DIS2026.pdf

15:10 Di-Higgs Production via gluon fusion in HEFT and SMEFT (17'+3')

In searches for physics beyond the Standard Model (BSM), bottom-up effective field theories (EFTs) such as the Standard Model EFT (SMEFT) and Higgs EFT (HEFT) have become crucial theoretical tools. In particular, Higgs pair production offers the opportunity to probe correlations among the couplings of one or two Higgs bosons to fermions and gauge bosons. In this context, it serves as a powerful test of the underlying EFT framework. In this talk, we confront the calculation and phenomenology of Higgs pair production via gluon fusion in the HEFT framework with those of the SMEFT up to dimension-8.

Speaker: Konstantin Schmid (University and INFN Padova)

DIS_2026_Schmid.pdf

15:30 Results on photon-photon scattering processes in ultra-peripheral Pb+Pb collisions with ATLAS (17+3')

In ultra-relativistic heavy-ion collisions, large rates of $\gamma\gamma$ processes arise from the intense electromagnetic fields generated by the colliding nuclei. These $\gamma\gamma$ interactions provide a powerful laboratory to study reactions that may be sensitive to physics beyond the Standard Model. In ultra-peripheral collisions (UPCs), where the impact parameter between the nuclei exceeds the sum of their radii, the final-state particles are predominantly produced back-to-back in the transverse plane, enabling precise and efficient event identification. This talk presents an overview of recent ATLAS measurements potentially sensitive to physics beyond the Standard Model. Measurements of differential cross-sections for $\tau$-lepton pair production are reported, providing constraints on the $\tau$-lepton anomalous magnetic moment. Results are also presented on measurements of light-by-light scattering, which can be used to set limits on the existence of gravitons or axion-like particles (ALPs). In addition, a search for monopole-pair production in UPCs is presented for monopole masses in the 20–150 GeV range. The results are compared with predictions from a leading-order model of spin-1/2 particle production via photon–photon fusion, as well as with a recently developed semi-classical model that includes non-perturbative cross-section calculations.

Speaker: Lydia Beresford

LB_DIS_2026.pdf

14:30 → 16:15 WG4 QCD with Heavy flavours and Hadronic Final States

14:30 New precise measurement of $e^+e^-\rightarrow \pi^+\pi^-$ with BABAR for muon g-2 prediction

A measurement of the key $e^+e^-\rightarrow \pi^+\pi^-$ cross section relevant for the hadronic vacuum polarization (HVP) is presented using the full BABAR data set. The analysis employs a novel method that does not rely on particle identification to separate pions and muons, and is therefore fully independent of the BABAR 2009 analysis. This result is expected to play an important role in clarifying the current situation, where significant discrepancies are observed between the extreme results reported by KLOE and CMD-3, which presently prevent a reliable averaging of the $e^+e^-\rightarrow \pi^+\pi^-$ cross sections for the determination of the HVP contribution to the muon anomalous magnetic moment.

Speaker: Isabella Garzia (Istituto Nazionale di Fisica Nucleare)

DIS2026-garziav2.pdf

14:50 Monte Carlo event generator tuning in the CMS experiment

Monte Carlo event generator tuning is essential for the accurate modeling of proton-proton collisions in the CMS experiment. Commonly used generators such as Pythia and Herwig rely on phenomenological models of the underlying event, including multiparton interactions, as well as color reconnection and other non-perturbative QCD components, whose parameters must be constrained using data. This talk presents an overview of how generator tuning is performed in CMS, highlighting key inputs, methodologies, and results.

Speaker: Mehmet Umut Ozyurda (Hacettepe University)

DIS-2026-MC-TUNES-CMS.pdf

15:10 NNLO QCD corrections to event shapes in di-photon production at the LHC

Photon pair production is an important benchmark process at the LHC, entering Higgs boson studies and new physics searches. It has been measured to high accuracy, allowing for detailed studies of event shapes in di-photon final states. In this talk, I present the NNLO QCD corrections to the production of di-photon final states at finite transverse momentum. The results are compared with ATLAS precision measurement.

Speaker: Weijie Feng (University of Zurich)

DIS2026_Feng.pdf

15:30 Light and charmed meson fragmentation measurements at Belle/BelleII

Fragmentation functions describe the formation of final-state hadrons from high-energetic partons. As they are non-perturbative objects they cannot be calculated from first principles in QCD but need to be measured. Especially e+e- annihilation is a clean tool to extract fragmentation functions since no hadrons exist in the initial state.
We report the recent measurements by Belle/Belle II of light and charmed mesons that decay into two or three pions or kaons as a function of the relative momentum fraction. These measurements will be used in global fragmentation fits and provide input to the semi-inclusive DIS program at the Electron-Ion-Collider. They can also improve the tuning of Monte-Carlo generators.

Speaker: Ralf Seidl (RIKEN)

2026_05_06_DIS_FF_Seidl.pdf

15:50 Open Discussion

14:30 → 16:15 WG5 Spin and 3D-structure

Convener: Tyler Kutz (Johannes Gutenberg University Mainz)

14:30 Precise measurement of the neutron $d_2$

In inclusive polarized lepton-nucleon deep-inelastic scattering, the twist-3 matrix element $d_2$ is defined as the third moment of a linear combination of the spin-structure functions $g_1$ and $g_2$. It is sensitive to quark-gluon correlations in the nucleon and has been interpreted as an average color Lorentz force acting on the struck quark, due to the remnant diquark system. While the neutron $d_2$ ($d_2^n$) has been measured by several experiments, previous extractions have required evolving $g_1$ and $g_2$ to common $Q^2$ because the relevant observables were obtained over a broad $Q^2$ range. Moreover, $d_2^n$ at high $Q^2$ has remained inconclusive due to the limited statistics. To evaluate $d_2^n$ more precisely, we measured double-spin asymmetries and unpolarized cross sections at two nearly constant $Q^2$ values, $\sim$3.0 GeV$^2$ and $\sim$6.0 GeV$^2$, with high statistics in inelastic scattering of longitudinally polarized electrons from polarized $^{3}$He nuclei, using the HMS and SHMS spectrometers in Hall C at Jefferson Lab. Our data provide a significantly improved determination of $d_2^n$ at intermediate and high $Q^2$ and offer a stringent test of lattice QCD. In this talk, we will present the analysis status and preliminary results.

Speaker: Minho Kim (Argonne National Laboratory)

DIS2026.pdf

14:50 Projected High Precision Measurements on the Spin Structure g1 for the Proton and the Neutron at EIC

The spin structure function $g_1$ is important for understanding the quark spin contribution to the overall spin of nucleons, which has been a long standing puzzle in nuclear physics. Through the $Q^2$ dependence of $g_1$, the structure function is also sensitive to the gluon spin contribution. In addition, it is important for testing the Bjorken sum rule and can provide a unique way of obtaining the strong coupling constant. $g_1$ can be measured via the longitudinal and transverse double spin asymmetry in polarized deep inelastic scattering, which has been tested at various fixed target experiments in the past. However, to better address the current open QCD questions as raised earlier, polarized data with wider kinematic coverage reaching low $x$ and high $Q^2$ region are needed. The ePIC detector at the future Electron Ion Collider aims to make high precision measurements of $g_1^p$ and $g_1^n$ from $ep$ DIS and $e^3\rm{He}$ DIS uncovering a large fraction of this previously unexplored area. The details of the experiment and measurement methods will be discussed in this presentation, along with a quantitative projected results estimated using the recent ePIC detector simulation and analysis.

Speaker: Win Lin (Stony Brook University)

WL_g1_DIS2026.pdf

15:10 Global QCD analysis of spin PDFs in the proton with high-$x$ and lattice constraints

We perform a comprehensive global QCD analysis of spin-dependent PDFs, combining all available data on inclusive and semi-inclusive DIS, as well as inclusive weak boson and jet production in polarized $pp$ collisions, simultaneously extracting spin-averaged PDFs and fragmentation functions. Including recent Jefferson Lab DIS data at high $x$, together with subleading power corrections to the leading-twist framework, allows us to verify the stability of the PDFs for $W^2 \geq 4$ GeV$^2$ and quantify the uncertainties on the spin structure functions more reliably. We explore the use of new lattice QCD data on gluonic pseudo-Ioffe time distributions, which, together with jet production and high-$x$ DIS data, improve the constraints on the polarized gluon PDF. The expanded kinematic reach afforded by the data into the high-$x$ region allows us to refine the bounds on higher-twist contributions to the spin structure functions, and test the validity of the Bjorken sum rule.

Speaker: Wally Melnitchouk (Jefferson Lab)

melnitchouk-new.pdf

15:30 Accessing nucleon transversity with one-point energy correlators

We propose a novel probe of the nucleon's transversity distribution, $h_1^q$, using the one-point energy correlator (OPEC), an infrared-and-collinear safe jet substructure observable. We demonstrate that in transversely polarized $p^{\uparrow}p$ collisions, the OPEC exhibits a single-spin asymmetry (SSA) with a clean $\sin(\phi_s - \phi_n)$ angular dependence. This method probes SSA over a much wider kinematic range in the angular scale $\theta_n$ compared to traditional measurements of hadron transverse momentum~$j_\perp$, establishing a complementary and systematically distinct channel to study the nucleon's three-dimensional structure at RHIC and the future Electron-Ion Collider.

Speaker: Wanchen Li (Fudan University)

WanchenLi_OPEC.pdf

15:50 Polarized Scattering at NLO+PS Accuracy in the POWHEG BOX

We present new Monte-Carlo tools for precision phenomenology in longitudinally polarized scattering processes, providing next-to-leading order QCD predictions matched to parton showers (NLO+PS) within the POWHEG BOX framework for di-jet production in polarized proton–proton collisions and polarized deep inelastic scattering. The generators are designed to deliver fully differential predictions for relevant observables to current and future spin-physics programs. We discuss the extensions required to consistently incorporate polarized initial states in the POWHEG formalism and study a range of observables for RHIC and for the upcoming Electron-Ion Collider. We assess the impact of parton-shower effects and selection criteria on key distributions, identifying kinematic regions where these effects are non-negligible and improve agreement with data or with higher-order predictions.

Speaker: Ignacio Borsa (University of Tübingen)

IB-DIS-Bologna-May26.pdf

14:30 → 16:00 WG6 Current upgrades and future experiments

Convener: Federico Lasagni Manghi (Istituto Nazionale di Fisica Nucleare)

14:30 Antiproton production measurement for indirect Dark Matter search at the AMBER experiment at CERN

Precise knowledge of inclusive antiproton production cross sections is essential for interpreting high-precision cosmic-ray antiproton measurements (e.g. AMS-02) and for maximizing the sensitivity of indirect searches for dark matter. In the energy domain where most secondary antiprotons are produced in the Galaxy, interactions involving protons and helium dominate, yet accelerator data—especially for p–He at low center-of-mass energy—are sparse. As a consequence, nuclear-production uncertainties limit the accuracy of the antiproton source term used in propagation models.
AMBER (NA66) is a fixed-target experiment at the CERN SPS M2 beam line that is going to provide high-statistics measurements of antiproton production in p–He and p–p/d collisions. In 2023, AMBER carried out an extensive measurement with a proton beam incident on a liquid helium ($^{4}$He) target, covering an unprecedented beam-momentum range from 60 to 250 GeV/c ($\sqrt{s_{NN}}$=10.7–21.7 GeV). Event-by-event beam proton tagging is performed with two CEDAR Cherenkov detectors located about 40 m upstream of the target. Final-state hadrons are reconstructed in the two-stage magnetic spectrometer and identified with the RICH-1 detector.
We present the analysis strategy and preliminary antiproton yields and statistical uncertainties for p–He collisions at $\sqrt{s_{NN}}$=18.9 GeV, binned in laboratory momentum and transverse momentum, as a first step toward the double-differential production cross section $d^{2}\sigma/(dp dp_T$). Luminosity and target-related systematics are controlled via a data-driven determination of the target geometry and position from the reconstructed primary-vertex distribution, complemented by acceptance and efficiency corrections. We also outline the 2024 data set acquired with liquid hydrogen and deuterium targets at 80, 160 and 250 GeV/c, enabling a data-driven separation of p–p and p–n contributions and a stringent test of a possible isospin-driven antineutron/antiproton production asymmetries. With individual cross-section measurements at the ~5% level, AMBER is expected to substantially reduce the dominant nuclear-production uncertainties in cosmic-ray antiproton predictions.

Speaker: Davide Giordano (Istituto Nazionale di Fisica Nucleare)

Giordano_DIS2026.pdf

14:50 Ultimate achievable precision from past and future DIS measurements

The HERAPDF2.0 parton densities represent the current state of the art in determining the longitudinal structure of the proton when using data from Deep Inelastic Scattering (DIS) experiments alone. Their precision is at the few percent level at intermediate Bjorken-x, but deteriorates fast for x-->1 and also below x~10$^{-3}$. The high x region in particular can also be constrained using LHC data, though at the price of increased theoretical complexity and currently with tensions between data sets. In this study we investigate how the picture may evolve with time in the future by using only DIS ingredients in proton PDF fits based on proposed new lepton-hadron colliders. We start by including simulated data from the US Electron Ion Collider (EIC), which are known to improve matters at large x. We then additionally add simulated data from the Large Hadron electron Collider (LHeC), which has been proposed as a future CERN facility. The LHeC is confirmed to potentially revolutionise the precision at both large and small $x$, even with EIC data are included. In the longer term the Future Circular Collider in ep mode (FCC_eh) may allow further progress at low $x$, extending the sensitivity towards $x=10^{-7}$; its impact is studied when added in addition to the EIC and LHeC. We also study the results of leaving the strong coupling as a free parameter in the fits. Once again, the LHeC and/or FCC-eh yield significant improvements even beyond the currently world-leading potential of an EIC determination.

Speaker: Katarzyna Wichmann (DESY)

kwichmann-ultimateDIS-dis26.pdf

15:10 Higgs and BSM physics at the LHeC

The Large Hadron electron Collider (LHeC) is the proposal to deliver electron-proton/nucleus collisions at CERN using the LHC beams and a 50 GeV electron beam from an Energy Recovery Linac. While initially foreseen [1] for concurrent electron-hadron and hadron-hadron operation, a standalone electron-hadron operation phase has been proposed [2] in view of the current LHC schedule. Thus, the LHeC becomes a bridge from the HL-LHC to the next flagship at CERN, and one of the possible projects in the 2026 Update of the European Strategy for Particle Physics [3], were the FCC-ee as plan A not feasible.
In this talk we review the Higgs physics studies at the LHeC. We present the standalone determination of the Higgs couplings. We then explore the impact of the improved extraction of PDFs+$\alpha_s$ at the LHeC on Higgs coupling determination at the HL-LHC, as well as the implications on the Higgs mass extracted in EW fits, and on the cross section through gluon-gluon fusion. We finally discuss the comparison of the extraction of couplings in different combinations of future accelerators, highlighting the role of the combination HL-LHC+LHeC.
[1] P. Agostini et al. (LHeC/FCC-he Study Group), J. Phys. G 48, 110501 (2021), arXiv:2007.14491 [hep-ex].
[2] F. Ahmadova et al., e-Print: 2503.17727 [hep-ex].
[3] The European Strategy for Particle Physics: 2026 Update - Recommendations by the European Strategy Group, https://cds.cern.ch/record/2950671/files/CERN-ESU-2025-002.pdf?version=1.

Speaker: Néstor Armesto (Universidade de Santiago de Compostela)

Armesto_DIS2026_06052026.pdf

15:30 Probing Cosmic Ray Composition and Muon-philic Dark Matter using GeV Muon sources

We propose here a set of new proposals and some prelimenary experimental results involving probing and knocking with muons (PKMu). There is a wealth of rich physics to explore with GeV muon beams either from dedicated beam or cosmic sourse. Examples include but not limited to: muon scattering can occur at large angles, providing evidence of potential muon-philic dark matter or dark mediator candidates; muon-electron scattering can be used to detect new types of bosons associated with charged lepton flavor violation; precise measurements of GeV-scale muon-electron scattering can be employed to probe quantum correlations.

Speaker: Mr Leyun Gao (Peking University)

Leyun_Gao-PKMu-20260504.pdf

15:50 ePIC PID performance in SIDIS processes at the Electron-Ion Collider

Particle Identification (PID) is a key requirement for the physics program of the future Electron-Ion Collider (EIC), particularly for Deep Inelastic Scattering (DIS) and Semi-Inclusive DIS (SIDIS) measurements. The EIC will provide unprecedented luminosity and wide kinematic coverage, enabling high-precision studies of the three-dimensional structure of nucleons through multi-differential observables. For this reason, robust PID capabilities are indispensable to perform high-precision and reliable measurements.

In this work, we present a performance study of the PID system of the ePIC detector, focusing on its impact on multi-dimensional SIDIS analyses. The study evaluates PID performance in terms of efficiency ($e$), purity ($p$), and a combined figure of merit defined as $1/(p\sqrt{e\cdot N})$, where $N$ is the yield scaled on the expected EIC luminosities. This quantity is directly related to the statistical precision of the reconstructed observables and provides a compact metric to estimate the interplay between detector performance and physics sensitivity.

The analysis is performed using a four-dimensional binning in the Bjorken fraction ($x_B$), scale of the process ($Q^2$), hadron energy fraction carried by the struck quark ($z$), and the transverse momentum carried by the identified hadron ($P_{hT}$). Multi-dimensional extractions are crucial for SIDIS studies, as the extraction of collinear Parton Distribution Functions (PDF) and Transverse Momentum Dependent (TMD) distributions relies on observables that depend simultaneously on these kinematic variables and on their correlations.

The results demonstrate how the ePIC detector's performance varies across the SIDIS phase space, identifying kinematic regions where PID performance plays a dominant role in limiting measurement precision. These studies provide essential input for the optimization of the ePIC detector design and have been included as a contribution to the ePIC experiment's pre-Technical Design Report (pre-TDR).

Speaker: Lorenzo Polizzi (Istituto Nazionale di Fisica Nucleare)

DIS2026-polizzi.pdf

16:15 → 16:30 Tea break - available from 16:00 to 17:00

16:30 → 18:30 WG1 Structure functions and parton densities

Convener: Aurore Courtoy (Instituto de Física, UNAM)

16:30 Theoretical Uncertainties on the determination of the strong coupling from Z pT

I will analyse the theoretical uncertainties inherent in the determination of the strong coupling from the transverse momentum (pT) spectrum of the Z boson. Such analyses require fine control of percent-level theoretical effects in small pT region, not only in terms of their magnitude but also of their shape and that of the corresponding theoretical uncertainties. This is theoretically extremely challenging. In this talk I will analyse the associated theoretical uncertainties via the novel theoretical nuisance parameter approach. In particular, I will focus on the perturbative uncertainty from missing higher orders in resummation, and that associated with the parton distribution functions.

Speaker: Thomas Cridge (University of Manchester)

TCridge_Alphas_ZpT_TheoryUncertainties.pdf

16:50 A simultaneous determination of $\alpha_s(m_Z)$ and $m_t$ from a global PDF analysis

We present a simultaneous determination of the strong coupling constant $\alpha_s(m_Z)$ and the top-quark mass $m_t$ within a global PDF analysis based on the public NNPDF framework. We consider a wide range of $t\bar{t}$ measurements, including both single- and double-differential observables, computed at NNLO QCD accuracy, and analyse their individual as well as combined impact on the joint $\alpha_s, m_t$ parameter space, while accounting for PDF evolution up to (approximate) N3LO QCD accuracy with QED corrections. Unique to our analysis are the inclusion of, first, toponium contributions around the $t\bar{t}$ threshold, second, state-of-the-art constraints on $\alpha_s$ from the lattice, and finally, a detailed sensitivity study of various ATLAS and CMS measurements. The last point will demonstrate explicitly how their combination requires one to refit the PDFs in order to correctly correlate uncertainties.

Speaker: Jaco ter Hoeve (University of Edinburgh)

JtH-DIS2026.pdf

17:00 Interplay of $\alpha_s$, $m_t$ and gluon parametrization in CT PDF extractions

Achieving percent-level accuracy and precision in parton distribution functions (PDFs) requires a careful optimization of the theoretical and methodological ingredients entering their determination. In this talk, we present a multidimensional correlation study based on multiple CT25 PDF fits at NNLO in QCD, aimed at investigating and quantifying the correlations among the strong coupling $\alpha_s(M_Z)$, the top-quark pole mass $m_t$,and the gluon PDF parametrization. We perform ${\cal O}(100)$ simultaneous fits using optimized combinations of recent high-precision differential cross-section measurements for top-quark pair production at the LHC, and illustrate the individual roles of the parameters contributing to the observed multidimensional correlations to understand their effect on the resulting PDFs.

Speaker: Tanishq Sharma (Michigan State University)

CT25_alphas_mtop_TS.pdf

17:10 Impact of PVDIS on the weak mixing angle and high-$x$ parton distributions

We discuss the impact of neutral current parity-violating deep-inelastic scattering of electrons from proton and deuterium targets, planned in future measurements at Jefferson Lab, on the determination of the weak mixing angle, $\sin^2\theta_W$, and PDFs at large parton momentum fractions $x$. Using the JAM global QCD analysis framework, we perform a new analysis incorporating data simulated at 11 and 22~GeV Jefferson Lab kinematics, accounting for radiative corrections in a factorized QED+QCD approach and uncertainties from higher twists in $\gamma Z$ exchange. We find that including future $A_{\rm PV}$ data could yield important constraints on the value of $\sin^2\theta_W$ at low $Q^2$ and the high-$x$ behavior of the strange quark PDF and the $d/u$ PDF ratio. Furthermore, the weak correlation between $\sin^2\theta_W$ and the $x$ dependence of the PDFs indicates that $A_{\rm PV}$ data can provide a robust determination of the weak mixing angle in a global QCD analysis.

Speaker: Richard Whitehill (Old Dominion University / Jefferson Lab)

DIS2026-WG1_RWhitehill.pdf

17:30 Optimization of factorization scale in QED Drell-Yan-like processes

The dependence of corrections due to the initial state radiation in electron-positron annihilation processes on the choice of the factorization scale is investigated. Different prescriptions of the factorization scale choice are analyzed within the leading and next-to-leading logarithmic approximations. Comparisons with the known complete two-loop results are used to optimize the scale choice.

Speaker: Andrej Arbuzov (Joint Institute for Nuclear Research)

arbuzov_DIS_2026.pdf

17:50 Two-Loop DGLAP Splitting Functions from Light Cone Perturbation Theory

We perform a two-loop calculation in Light Cone Perturbation Theory (LCPT) to evaluate the next-to-leading order nonsinglet splitting function. Our calculation demonstrates the methodology and feasibility of performing higher order calculations in LCPT. Since in Hamiltonian perturbation theory the longitudinal $k^+$ momentum is always positive, poles in $1/k^+$ can be regularized by a simple cutoff which cancels in physical results, without any associated ambiguities. For transverse momentum integrals we use dimensional regularization. Developing methods for loop calculations in LCPT paves the way for a systematical, automatizable procedure for precision calculations in this framework with a transparent physical partonic interpretation. This can provide a standard framework in higher order calculations in the gluon saturation regime of QCD.

Speaker: Mikko Seppälä (University of Helsinki)

dis26_seppala.pdf

18:10 QED Effects in PDFs

With the increasing precision of PDF determinations, previously small effects require closer analysis. QED effects in PDFs are one such example, typically representing a percent effect, subtleties in their application can result in differences between the global PDF fitting groups. We analyse these and present the current status, as well as impacts on Higgs production cross-sections.

Speaker: Thomas Cridge (University of Manchester)

TCridge_QED_Effects_PDFs.pdf

16:30 → 18:35 WG2 Small-x, diffraction and vector mesons

Convener: Michael Pitt (CERN)

16:30 High-energy QCD phenomenology with next-to-leading order BFKL eigenfunctions

A general framework for the description of semi-hard scattering amplitudes in perturbative Quantum Chromodynamics (pQCD) is presented, based on the use of the next-to-leading order eigenfunctions of the Balitsky–Fadin–Kuraev–Lipatov (BFKL) kernel constructed by Chirilli and Kovchegov. Formal aspects related to the consistency with the corresponding formulation employing leading-order BFKL eigenfunctions are discussed. The phenomenological implications of adopting either representation are investigated through a comparative analysis of the resulting amplitudes in selected high-energy processes.

Speaker: Ada Polizzi (Istituto Nazionale di Fisica Nucleare)

High-energy QCD phenomenology with next-to-leading order BFKL eigenfunctions.pdf

16:50 Diffractive Structure Functions from JIMWLK Evolution

We compute diffractive structure functions from Wilson line configurations whose energy evolution is given by the JIMWLK equation. We use a JIMWLK evolution setup that has already been constrained with exclusive vector meson production data from HERA. Our results can be compared to HERA measurements and also extended to heavy nuclei. In particular we can calculate predictions for the nuclear modification factor and diffractive-to-total cross section ratios at the EIC.

Speaker: Pyry Runko (University of Jyväskylä)

Runko-DIS2026-DiffStructFuncJIMWLK.pdf

17:10 Searches for QCD instantons with forward proton tagging

Although the QCD instanton has been intensively searched for in several experiments, and is currently being searched at LHC, it has not so far been observed. In 2208.14089 we study the possibility to observe heavy ($M_{\rm inst}>$ 60 GeV) QCD instantons at the LHC in the diffraction mode, i.e. in events with one or two tagged leading protons which are accompanied by large rapidity gaps. The presented analysis provides a detailed look into the experimental situation and accounts for detector and pile-up effects. We show that the expected instanton signal in a single-tagged configuration is strongly affected by central detector and pile-up effects but observable. For double-tagged approach the combinatorial background overwhelms the expected signal. Possible improvements lie in adding time information about tracks at central and forward rapidities.

Speaker: Marek Tasevsky (Institute of Physics of the Czech Academy of Sciences, Prague, Czech Republic)

Tasevsky_060526.pdf

17:30 Inclusive diffraction in eA at small x with the Sartre event generator

Inclusive diffraction in eA is seen as a first year measurement of saturation physics at the electron-ion collider. Therefore it is crucial to be able to simulate and generate inclusive diffractive events at small momentum fractions. This new version of Sartre is the first event generator for inclusive diffraction at small x in electron-ion collisions. Sartre calculates the amplitudes in the dipole model where the virtual photon splits into either a quark-antiquark dipoles, or the higher Fockstate of a quark-antiquark-gluon double dipole. Once the partonic final state has been generated, we use the Lund string fragmentation model in Pythia 8 for hadronisation. In order to enable fast event-generation we store lookup tables of the cross-sections on disk, which are created using machine learning techniques. There is also an extension to heavy flavours produced in ultra-peripheral collisions at RHIC and the LHC. I will show results of both inclusive and exclusive observables resulting from our simulations.

Speaker: Tobias Toll (Indian Institute of Technology Delhi)

SartreInclusiveDiffractionDIS2026_4.pdf

17:50 Diffractive deep inelastic scattering in the dipole picture: the $q\bar{q}g$ contribution in exact kinematics

We report on our recent work [1] where we compute the $q\bar q g$ contribution to the diffractive structure functions in high-energy deep inelastic scattering (DIS). The obtained result corresponds to a self-contained, finite part of the next-to-leading-order (NLO) contribution to the diffractive cross section. Previous phenomenological applications have included this contribution only in the high-$Q^2$ or high-$M_X^2$ limits in the case of a soft gluon, and we numerically demonstrate that these existing estimates do not provide a good approximation for the full $q\bar q g$ contribution. Furthermore, we demonstrate that in addition to the soft gluon contribution, there is an equally important soft quark contribution to the diffractive structure functions at high $Q^2$. We also report on our ongoing work to include the remaining contributions in order to compute the diffractive DIS structure functions at NLO.

[1] A. Kaushik, H. Mäntysaari and J. Penttala, Diffractive deep inelastic scattering in the dipole picture: the $q\bar q g$ contribution in exact kinematics, arXiv:2510.24171 [hep-ph].

Speaker: Abhiram Kaushik Badrinarayanan (University of Jyvaskyla)

DIS026_AK.pdf

18:10 Small-x Factorization in the Target Fragmentation Region of DIS

Single-inclusive particle production in Deep Inelastic Scattering (DIS) provides a powerful probe of the three-dimensional partonic structure of hadrons and nuclei. While most small-x studies focus on the current fragmentation region of DIS, we investigate particle production in the target fragmentation region, which is naturally described in terms of fracture functions.

Focusing on longitudinally polarized virtual photons in the kinematic regime where the virtuality is much larger than the transverse momentum of the produced hadron/jet Q2≫PT2, we show that single-inclusive jet and hadron production in the target hemisphere yields a leading-power contribution that is not suppressed by PT /Q. We demonstrate that, at small Bjorken-x, the differential cross section factorizes in terms of extended quark and gluon fracture functions, for which we derive explicit analytic expressions within the Color Glass Condensate effective theory. Remarkably, the resulting factorized results satisfies a transverse-momentum-dependent analogue of the Altarelli–Martinelli relation.

We present numerical results for the extended quark and gluon fracture functions. Furthermore, we comment on the interplay between our results and the diffractive fracture functions, as well as the connection to nucleon-energy correlators.

Speaker: Paul Caucal (SUBATECH, Nantes Université, IN2P3/CNRS)

caucal_DIS-2026_FF.pdf

16:30 → 18:15 WG6 Current upgrades and future experiments

Convener: Domenico Elia (Istituto Nazionale di Fisica Nucleare)

16:30 Run-3 Performance of the ATLAS Muon Spectrometer and Upgrades for the High-Luminosity LHC

With the start of the Long Shutdown 3 (LS3) of the LHC in July 2026, lasting nearly four years, ATLAS will enter the implementation phase of the major detector upgrades required for High-Luminosity LHC operation. The Muon Spectrometer will undergo a substantial transformation to meet the stringent operational demands imposed by the increased luminosity, trigger rates, and radiation levels foreseen at the HL-LHC. A comprehensive replacement of the front-end and readout electronics for the Monitored Drift Tube (MDT), Resistive Plate Chamber (RPC), and Thin Gap Chamber (TGC) systems is planned to ensure compatibility with the higher trigger rates and extended latencies of the new level-0 trigger. A key element of the upgrade concerns the RPC system. New RPC chambers featuring 1 mm gas gaps will be installed in the inner barrel layer, significantly improving trigger acceptance, rate capability, and robustness under high background conditions. These upgrades play a central role in maintaining efficient and selective muon triggering at HL-LHC luminosities. In parallel, MDT chambers will be integrated into the level-0 trigger to sharpen the transverse momentum threshold, and selected inner barrel MDTs will be replaced by small-diameter MDT chambers to optimize performance in high-occupancy regions. In the barrel–endcap transition region, new TGC triplet chambers will replace the existing doublets to reduce the high trigger rates caused by random coincidences. In addition, the power distribution systems and associated electronics for the RPC, TGC, and MDT detectors will be upgradeded to address component obsolescence, ageing, and radiation tolerance requirements. This contribution will present an overview of the upgrade strategy and challenges. Results from prototype and production studies, as well as the current project status, will be reported, together with a discussion on the expected performance improvements and their impact on muon triggering, reconstruction, and physics results at the High-Luminosity LHC.

Speaker: Gabriella Gaudio (Istituto Nazionale di Fisica Nucleare)

DIS2026_ATLAS_MS_gaudio.pdf

16:50 Progress of the Super Tau Charm Facility project in China

The Super Tau-Charm Facility (STCF) is a new-generation high-luminosity electron-positron collider proposed in China. It will operate in an energy range of 2-7 GeV with a luminosity higher than 0.5*10^35 cm^2 s^-1 at 4 GeV. The STCF can produce a large number of hadrons and tau leptons in a clean environment, serving as a unique and powerful tool for studying how quarks form hadrons to understand the quark confinement, as well as revealing the mystery of the space-time symmetry of fundamental interactions with unprecedented precision. The STCF physics program covers a broad spectrum of physics topics, placing stringent demands on the performance of the STCF accelerator and detector. The STCF detector and accelerator conceptual designs have been completed and published. A full accelerator and detector technology R&D program was established and has been progressing rapidly. In this report, the STCF physics program will be introduced following an overview of the STCF project. The STCF accelerator and detector conceptual designs and R&D progress will then be presented.

Speakers: Jinlong Zhang (Shandong University), Wenbiao Yan (USTC), Prof. Xingtao Huang (Shandong University)

STCF-DIS-2026-v1.pdf

17:10 MUSIC: a detector concept for 10 TeV µ⁺µ⁻ collisions

The full exploitation of the physics potential of a multi-TeV muon collider critically depends on the detector’s ability to cope with unprecedented levels of machine-induced backgrounds. This contribution introduces the MUSIC (MUon System for Interesting Collisions) detector concept and presents its expected performance in the context of √s = 10 TeV muon–antimuon collisions. MUSIC is specifically designed to mitigate the impact of machine-induced backgrounds while preserving high efficiency and precision in the reconstruction of physics events.

The detector features an advanced all-silicon tracking system, a semi-homogeneous lead–fluorite crystal electromagnetic calorimeter, an iron–scintillator sampling hadronic calorimeter, and a superconducting solenoid providing a 5 T magnetic field. Detailed detector simulations including the dominant machine-induced background sources are presented. The results demonstrate robust tracking performance, excellent photon, electron, and jet reconstruction capabilities, and strong jet flavor identification, highlighting the strong potential of the MUSIC detector for physics studies at a high-energy muon collider.

Speaker: Lorenzo Sestini (Istituto Nazionale di Fisica Nucleare)

MUSIC_DIS2026.pdf

17:30 The ePIC-dRICH streaming readout system

The investigation of the nucleon structure is one of the primary goals of the ePIC experiment at the future Electron–Ion Collider. Considering both inclusive and exclusive processes, ePIC will access unprecedented ranges in Q$^2$ and Bjorken x. The dual-radiator RICH (dRICH) detector is a key component of the ePIC Particle Identification (PID) system and is essential for the reconstruction of hadrons produced in high-Q$^2$ scattering events. Covering the pseudorapidity range $1.5< \eta <3.5$, the dRICH ensures $\pi$/K/p separation from $\sim3$ to $\sim 50$ GeV/c thanks to two Cherenkov radiators. More than 300 thousand 3x3 mm$^2$ SiPMs are employed as photosensors, each of them representing one readout channel. Given an expected radiation dose of $\sim6\cdot10^{10}$ 1-MeV neq/cm$^2$, radiation damage to the SiPMs leads to an increase in the dark count rate (DCR), which constitutes the main limitation to single-photon resolution. Mitigation strategies based on low-temperature operation and in-situ annealing allow the DCR to be contained below 300 kHz after $\sim200$ fb$^{-1}$ of integrated luminosity.
The highest data throughput in ePIC of $\approx 7$ Tbit/s is expected from the dRICH readout system, primarily due to the DCR contribution. To address this challenge, efficient data-reduction techniques have been developed together with a streaming readout architecture segmented into 1248 Photon Detection Units (PDUs). Each PDU integrates four matrices of 64 SiPMs each, along with front-end electronics based on 4 ALCOR ASICs and an FPGA-based Readout (RDO) card. The ALCOR ASICs generate precise timestamp data, which are aggregated by the RDO card and streamed to the ePIC DAQ system via a 10 Gb/s optical link.
The data-push readout architecture of the dRICH detector will be presented, focusing mainly on the front-end and readout boards. A data throughput of $\approx 1.4$ Tbit/s is achievable using different data reduction methods that will be shown, highlighting the main role of the DAQ architecture design. Finally, results of prototype PDU readout will be discussed, in terms of data throughput, together with future studies exploiting the full bandwidth available of the selected optical link.

Speaker: Sandro Geminiani (Istituto Nazionale di Fisica Nucleare)

20260506[DIS_SG].pdf

16:45 → 18:50 WG3 Electro-weak physics/higgs/top and BSM: BSM Physics

Conveners: René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

16:45 Searches for heavy and vector-like fermions, and leptoquarks with the ATLAS and CMS experiments (22'+3')

The Standard Model of particle physics explains many natural phenomena yet remains incomplete. Leptoquarks (LQs) are hypothetical particles predicted to mediate interactions between quarks and leptons, bridging the gap between these two fundamental classes of particles. Vector-like quarks (VLQs) and vector-like leptons (VLLs) lie at the heart of many extensions seeking to address the Hierarchy Problem, as they can naturally cancel the mass divergence for the Higgs boson. This talk will present new results from LQ and VLQ searches with the ATLAS detector as well as heavy fermion searches with the CMS detector using proton-proton collision datasets at the LHC.

Speaker: Carlo Di Fraia (Istituto Nazionale di Fisica Nucleare)

DIS2026_cdifraia_v1.pdf

17:10 Dark sector searches at LHCb (17'+3')

The LHCb detector at the LHC provides unique coverage in the forward rapidity region (2<$\eta$<5). Its flexible trigger system enables the efficient recording of low-mass states, while the high-precision vertex detector allows for excellent separation between primary interactions and secondary decays. These capabilities make LHCb particularly powerful in exploring regions of phase space relevant to searches for both prompt and long-lived particles. A selection of searches will be presented, including searches for heavy neutral leptons and axion-like particles.

Speaker: Andrii Usachov (Nikhef and VU Amsterdam)

ausachov_DIS_2026_LHCbLLPs.pdf

17:30 Searches for Long-lived Particles, Exotic Heavy Resonances and Dark Matter with the ATLAS detector (22'+3')

Various theories beyond the Standard Model predict new physics phenomena that require dedicated and unconventional reconstruction techniques and background estimation strategies. Examples include displaced decays from long-lived particles scenarios or Dark Matter models where the target particles fall below standard trigger thresholds. These signatures often challenge traditional search strategies and demand innovative approaches to detection and analysis. The talk will focus on the most recent results using 13 and 13.6 TeV pp collision data collected by the ATLAS detector.

Many extensions of the Standard Model predict new heavy particles that could appear as resonances decaying into quarks, leptons or photons, or phenomena that require dedicated and unconventional reconstruction techniques and background estimation strategies. Examples include displaced decays from long-lived particles scenarios or Dark Matter models where the target particles fall below standard trigger thresholds.. The talk will focus on the most recent results using 13 and 13.6 TeV pp collision data collected by the ATLAS detector.

Speaker: James Smith (University of Manchester)

DIS2026_JamesSmith_FinalDraft.pdf

17:55 Searches for Supersymmetry at the ATLAS and CMS experiments (22'+3')

Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. Naturalness arguments also favour supersymmetric partners of the gluons and third-generation quarks with masses light enough to be produced at the LHC. This talk will highlight the most recent results of searches performed by the ATLAS and CMS experiment for supersymmetric particles, considering both electroweak and strong production modes. With increasing mass bounds on more classical MSSM scenarios other variations of supersymmetry become increasingly interesting. Results for compressed, non-minimal, and R-parity violating scenarios and recent interpretations in the context of the pMSSM are also presented.

Speaker: Yuchen Cai (Istituto Nazionale di Fisica Nucleare)

YuchenCai-DIS2026.pdf

16:45 → 18:30 WG4 QCD with Heavy flavours and Hadronic Final States

16:45 Recent B-Physics Results from ATLAS

Studying heavy-flavour hadron properties provides a extensive tests for various QCD predictions as well as a means to probe the Standard Model validity. ATLAS experiment, being a general-purpose detector at LHC, is particularly successful in such measurements with final states involving muons, thanks to large collected integrated luminosity and precise muon reconstruction and triggering. This talk will overview the recent ATLAS results on b hadron production and decay properties and spectroscopy of exotic states.

Speaker: Ondrej Kovanda (University of Oregon (US))

OKovanda_DIS2026_V3.pdf

17:05 Dead cone measurement in b-jets at CMS

The CMS collaboration presents direct measurement of the dead-cone effect in b-jets using $\sqrt{s}=13$ TeV proton-proton collision data. By applying iterative declustering to b-jets from dileptonic $t\bar{t}$ events, we uncover the angular distribution of soft emissions. The unfolded results demonstrate the suppression of collinear gluon radiation characteristic of the heavy-quark parton shower, confirming QCD predictions relative to light quarks.

Speaker: Andris Potrebko

Andris_P_DIS_2026_05_06.pdf

17:25 Heavy-quark production in deep-inelastic scattering – Mellin moments of structure functions

We compute Mellin moments of the heavy-quark structure functions in deep inelastic
scattering at next-to-leading order in quantum chromodynamics, retaining their full
dependence on the heavy-quark mass. Using the optical theorem and the operator
product expansion, we derive analytic results for fixed Mellin moments N = 2 to 22
of the structure functions F2 and FL. Our results reproduce the known expressions in
the relevant asymptotic limits, in particular for virtualities of the exchanged photon
Q much larger than the heavy-quark mass m, and are in agreement with existing
parametrizations of the next-to-leading-order coefficient functions. The computational
set-up developed in this work also provides a direct pathway toward extending these
calculations to next-to-next-to-leading order.

Speaker: Marco Klann (University of Hamburg)

DIS2026.pdf

17:45 Unraveling QCD dynamics with heavy quark energy correlators

Heavy-flavor jets and their substructure provide a unique window into the role of quark mass on QCD radiation and its modification in nuclear matter. In this work, we investigate heavy-quark energy-energy (EEC) correlators that are explicitly sensitive to mass effects, focusing on angular correlations, energy flow, and the dead-cone effect. We demonstrate how the finite mass of charm and bottom quarks reshapes the intra-jet radiation pattern, leading to characteristic suppressions at small angles and measurable deviations from massless jet expectations. Using effective field theory analysis, we extend the calculation of these observables to reactions with nuclei to show medium-induced radiation competes with vacuum mass suppression, resulting in a nontrivial modification of jet substructure. Specifically, we identify regimes where the jet substructure is dominated by the heavy quark mass, leading to qualitatively and quantitatively different behavior of the EEC in nuclear matter, and obtain new analytic results for the energy loss of heavy quark jets. We discuss the charm and bottom jet energy-energy correlators modification in semi-inclusive DIS at the EIC, and further demonstrate how the formalism can be tested in small collision system at current facilities.

Speaker: Ivan Vitev (LANL)

HeavyEEC2026fin.pdf

18:05 Heavy-quark contributions to the DIS structure functions $F_4$ and $F_5$ at NLO in the ACOT scheme

Historically, theoretical and experimental efforts in Deep Inelastic Scattering have focused on the structure functions $F_1$, $F_2$, and $F_3$, largely neglecting $F_4$ and $F_5$. These structure functions are kinematically suppressed by the square of the lepton mass and are therefore relevant primarily in processes involving heavy leptons, such as the tau. However, the proposed SHiP experiment at CERN and recent high-energy tau neutrino observations by IceCube have renewed interest in these functions, creating a demand for precise theoretical predictions.In this work, we present a comprehensive analysis of the heavy-quark contributions to $F_4$ and $F_5$ at next-to-leading order in perturbative QCD. We utilize the ACOT scheme, a variable flavor number scheme that naturally handles heavy-quark mass effects and the resummation of quasi-collinear logarithms. We extend previous ACOT calculations for the standard structure functions to include $F_4$ and $F_5$. These results provide a robust framework for interpreting future experimental data and offer valuable insights into gluon and strange quark distributions at low Bjorken-$x$.

Speaker: Tomas Jezo (University of Münster)

TJezo_DIS26_WG4.pdf

18:15 Open Discussion

16:45 → 18:15 WG5 Spin and 3D-structure

Convener: Jan Matousek (Charles University, Prague)

16:45 PHENIX-Spin Highlights and Recent Results

After decommissioning in 2016, PHENIX continues releasing new results making significant contribution to our understanding of the nucleon’s spin structure on partonic level and parton dynamics within the polarized nucleon. In this talk we summarize the highlights of the PHENIX spin program from longitudinally and transversely polarized proton-proton collisions as well as from transversely polarized proton collisions with nuclei. We discuss in more detail the most recent results for transverse single spin asymmetry in forward eta-meson production, presented as a function of xF and pT, and compared to pi0-meson asymmetries and Twist-3 calculations (arXiv: 2509.13497).

Speaker: Alexander Bazilevsky (Brookhaven National Laboratory)

PHENIX_Spin_DIS26.pdf

17:05 sPHENIX Measurement of Neutral Meson, Photon and inclusive Jet Transverse Single Spin Asymmetries

Sizeable Transverse Single Spin Asymmetries have been observed at large $x_{\mathrm{Feynman}}$ (TSSAs) since the mid-1970s with fixed-target experiments, and were confirmed at the Relativistic Heavy Ion Collider experiments up to higher energy. The TSSAs are an important probe for non-perturbative spin-momentum correlations both in initial- and final-state strong nuclear interactions. They are described within two complementary frameworks: the collinear twist-3 (CT3) and the Transverse-Momentum-Dependent (TMD) schemes. We show the most recent measurements of TSSAs in inclusive production of $\pi^0$ and $\eta$ mesons obtained at the sPHENIX experiment, as a function of the meson transverse momentum $p_{\mathrm{T}}$ and $x_{\mathrm{Feynman}}$. The sPHENIX apparatus includes a large acceptance granular electromagnetic calorimeter (EMCal), as well as a high data rate plus trigger system, thus sampling 107 $\mathrm{pb}^{-1}$ of transversely polarized $p^\uparrow+p^\uparrow$ data during the RHIC run of 2024. This allows us to measure TSSAs in a kinematic region that spans central rapidity up to moderate forward rapidity ($0 < \eta < 2$), extending significantly the kinematic coverage given by previous RHIC measurements. In the central region at small $p_{\mathrm{T}}$, and thus at small $x_{\mathrm{Feynman}}$, TSSAs are particularly sensitive to gluon contributions and allow to constrain the collinear twist-3 trigluon functions as well as the gluon Sivers TMD functions.

Speaker: Ralf Seidl (RIKEN)

2026_05_06_sPHENIX_Seidl.pdf

17:25 Extraction of genuine twist-3 distribution from data

The twist-three parton distribution functions are given by quark-gluon-quark matrix elements, and encode quantum interference between quark-gluon-quark states. I present the determination of the genuine twist-3 distribution directly from experimental data. The analysis combines observables described by collinear and transverse-momentum-dependent factorization theorems within a unified global fit, incorporating a complete leading-order QCD evolution at the twist-three level. The extracted distributions reveal a clear flavor-dependent patterns and distinct from zero at a statistically significant level (2−3σ). These findings provide the first quantitative evidence for quark-gluon-quark correlations within the proton, revealing its genuinely quantum nature and opening a new direction for precision studies of partonic correlations.

Speaker: Alexey Vladimirov

DIS_AV.pdf

17:45 Probing the Eikonal Spin-Dependent Odderon: Challenges and Opportunities for the gluon Sivers function

The gluon Sivers function (GSF) is a central object in the study of the proton's 3D structure, encoding the intrinsic correlation between gluon transverse momentum and the transverse spin of the nucleon. Beyond its importance for proton tomography, the GSF fundamentally links parton orbital angular momentum and single spin asymmetries to the spin-dependent Odderon, rendering it particularly interesting from both theoretical and phenomenological perspectives.

In this talk, I will present results for the GSF within an eikonal model of the proton, where the Fock space is truncated at its valence-quark content. Numerically evaluating the C-odd cubic color charge correlator reveals a novel logarithmic behavior for the GSF at low $|k_\perp|$, signalling potentially large non-perturbative contributions. A key consequence of this behavior, when paired with the sum rule $\int\mathrm{d}^2k_\perp f_{1T}^{g\perp}(x,k_\perp) = 0$, is that higher $|k_\perp|$-moments of the GSF are suppressed. This suppression poses a significant challenge for the measurement of the collinear tri-gluon PDF, i.e. the $|k_\perp|^2$ moment of the GSF. Finally, I assess the phenomenological viability of various channels.

Speaker: Florian Hechenberger (Stony Brook University)

hechenberger_dis26.pdf

18:05 Matching relations for gluon TMDs up to one-loop accuracy

A fundamental ingredient for phenomenological studies of the three-dimensional (3D) momentum structure of the nucleon is provided by matching relations. These relations constrain the functional form of 3D parton distributions by connecting them to their collinear counterparts. For quark transverse-momentum–dependent distributions (TMDs), matching relations are known at one-loop accuracy, including contributions up to twist-3. In contrast, for gluon distributions such relations have so far been established only at leading twist.

In this talk, I will present new results for gluon TMDs at tree level and one loop, including twist-3 contributions. At tree level, I will discuss the matching relations for both T-even and T-odd distributions, incorporating the complete series of mass corrections. At one-loop accuracy, the main result is the derivation of a Wandzura–Wilczek–type relation for the gluon worm-gear T distribution.

Speaker: Alessio Carmelo Alvaro (Istituto Nazionale di Fisica Nucleare)

Alvaro_DIS26.pdf

20:00 → 22:00 Social dinner

Thursday 7 May

09:00 → 10:20 WG1 Structure functions and parton densities

Convener: Marco Bonvini (Istituto Nazionale di Fisica Nucleare)

09:00 Studies of N3LO corrections and resummation scale uncertainties in fits to DIS data using xFitter

We investigate the impact of recently computed N3LO corrections to QCD splitting and deep-inelastic scattering (DIS) coefficient functions on fits of parton distribution functions (PDFs) using the xFitter framework. By comparing fits performed at different perturbative orders, we analyze the resulting modifications to the PDFs and their associated uncertainties, incorporating correlated experimental errors. The results demonstrate the importance of N3LO corrections and highlight the need for further theoretical refinement in the low-x regime. Furthermore, we study the impact of resummation-scale variations on the splitting functions and on the strong coupling constant $\alpha_S$ . These variations introduce a significant additional uncertainty in the PDFs that has not been considered previously. We study the impact of this uncertainty on fits of HERA DIS data and its implications for predictions of top quark pair production at the LHC.

Speaker: Dr Francesco Giuli (Istituto Nazionale di Fisica Nucleare)

FGiuli_xFitter_DIS26_NEW.pdf

09:20 Toward N$^3$LO CT global PDF analyses: GMVFN schemes and DGLAP evolution in QCD

In this talk, we discuss two aspects of the ongoing efforts of the CTEQ–TEA group toward global parton distribution function (PDF) analyses beyond NNLO in QCD.
First, we present the realization of an intermediate ACOT-like general-mass variable flavor number (GMVFN) scheme for deep-inelastic scattering (DIS) at approximate next-to-next-to-next-to-leading order (aN$^3$LO) in QCD. Using the DIS structure functions $F^{c,b}_{2,L}$, we illustrate the main features of this scheme and discuss our ongoing work toward the full ACOT-MPS formulation at N$^3$LO.
Second, we present a generalization of the $x$-space Candia algorithm to N$^3$LO in QCD for solving the DGLAP evolution equations for unpolarized parton densities in the nucleon. The algorithm is based on logarithmic expansions of the solution and can be extended to all orders in QCD. An expansion equivalent to the exact DGLAP solution at N$^3$LO is presented in the non-singlet sector. We show results for approximate N$^3$LO PDFs evolved using the most recent approximations to the N$^3$LO splitting functions, together with a benchmark comparison against the HOPPET-v2 code.

Speaker: Marco Guzzi (Kennesaw State University)

DIS2026-MGuzzi.pdf

09:40 MSHT N^3LO PDF update

We present an update of the MSHT20 approximate N^3LO PDFs. This is based on
the inclusion of updated estimates of the N^3LO splitting functions and their
uncertanties, the final calculation of transition matrix elements and other
correponding theoretical improvements to the hard cross sections, particularly
for DIS data. We consider the impacts of the update on phenomeology at the LHC.

Speaker: Thomas Cridge (University of Manchester)

TCridge_MSHT_aN3LO_updates.pdf

10:00 The four-loop non-singlet splitting functions

Complete N3LO predictions require knowledge of the splitting functions at four loops. In this talk, I discuss our calculation of the four-loop non-singlet splitting functions from off-shell operator matrix elements. We obtain complete results with exact x-dependence for all non-singlet splitting functions and extract the virtual and rapidity anomalous dimensions in analytical form.

Speaker: Vasily Sotnikov (University of Zurich)

sotnikov_DIS2026_ns_split.v1.pdf

09:00 → 10:30 WG3 Electro-weak physics/higgs/top and BSM: EFT

Conveners: René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

09:20 EFT measurements in ATLAS (17'+3')

Effective Field Theories (EFT) offer a consistent means to combine a broad scope of measurements to probe the potential boundaries of phenomena beyond the Standard Model. To maximize the search potential, various efforts are focused on improving the measurement precision of EFT wilcon coefficients, by combining multiple relevant results. This talk will discuss the recent EFT combination results from ATLAS, covering results from Higgs, electroweak, and top-quark sectors.

Speaker: Lydia Brenner (CERN)

EFT measurements in ATLAS (1).pdf

09:40 Global fits at future colliders with the SMEFiT framework (17'+3')

In the context of the European Strategy for Particle Physics 2026 Update, we present projections for the new physics reach of future high-energy colliders using the latest version of the SMEFiT framework, with a focus on near-term electron-positron colliders (FCC-ee, LEP3, CEPC, and LCF). We quantify the sensitivity of these colliders to the SMEFT parameter space in a global analysis, where we include renormalization group evolution effects and NLO corrections to the EFT cross-sections. We also assess the impact of different theory uncertainty scenarios. The results of the global analysis are presented in terms of bounds on Wilson coefficients and effective couplings, providing a detailed picture of the potential of these colliders to probe physics beyond the Standard Model.

Speaker: Marion Thomas (Max Planck Institut für Physik)

MarionThomas_DIS26.pdf

10:00 Fit of Four-Fermion Operators through Drell-Yan data (8')

The Standard Model (SM) of particle physics describes the fundamental particles and their interactions with remarkable precision. Yet, it cannot explain key mysteries such as the nature of dark matter, the role of gravity, or why the universe contains more matter than antimatter.

With no new particles directly observed at the Large Hadron Collider (LHC), the most promising approach is to search for indirect signs of new physics. In fact, even very heavy, out-of-reach particles can subtly affect well-measured processes, leaving detectable imprints.

The Standard Model Effective Field Theory (SMEFT) provides a systematic, model-independent framework to capture these effects. It extends the SM by adding corrections characterized by parameters called Wilson coefficients, which can be constrained by experiments.

In this work, we constrain Wilson coefficients for the Drell–Yan process, in which a quark and an antiquark collide to produce a pair of leptons. This process is precisely measured and sensitive to several SMEFT corrections. We focus in particular on dimension-6 four-fermion operators, examining whether they can hint at new physics.

Ultimately, the goal is to exploit all available data for this process to probe physics beyond the Standard Model.

Speaker: Martina Fusi (University of Southampton)

DIS2026 - Bologna-1.pdf

10:08 PDF and BSM interplay in the top and Drell-Yan sector (8')

Indirect searches for new physics increasingly rely on precise theoretical predictions in the high-energy tails of the distributions, with Parton Distribution Functions (PDFs) being one of the main bottlenecks.
In this talk, I explore the interplay between the fits of Standard Model Effective Field Theory (SMEFT) Wilson coefficients and PDFs in two key sectors at the LHC, the Drell-Yan and the top sector. I explore two complementary strategies for robust new physics searches, aimed to mitigate the risk of absorbing new physics effects into the PDF determination and to better constrain PDFs in the large Bjorken-$x$ region : (i) fitting the PDFs and SMEFT parameters simultaneously, and (ii) fitting them separately with a “conservative” determination of the PDFs, using only observables that can safely be considered SM–like. I compare both methodologies in controlled closure tests in a realistic High-Luminosity LHC (HL-LHC) scenario. I conclude by proposing best-practice recommendations for robust indirect new physics searches in the Drell-Yan and top sectors at hadron colliders.

Speaker: Ella Cole

DIS2026_Ella_Cole.pdf

09:00 → 10:45 WG4 QCD with Heavy flavours and Hadronic Final States

09:00 High-precision QCD physics at FCC-ee

The electron-positron stage of the Future Circular Collider (FCC-ee) is aiming at direct and indirect searches for physics beyond the SM in a new 91-km tunnel at CERN. In addition, the FCC-ee offers unique possibilities for high-precision studies of the strong interaction in the clean environment provided by e$^+$e$^-$ collisions, thanks to its broad span of center-of-mass energies, ranging from the Z pole to the top-pair threshold, and its huge integrated luminosities yielding $\mathcal{O}(5\times 10^{12})$ and $\mathcal{O}(2\times10^8)$ jets from Z and W bosons decays respectively, $\mathcal{O}(2\times 10^5)$ pure gluon jets from Higgs boson decays, as well as $\mathcal{O}(2\times10^6)$ top quarks. In this contribution, we will summarize the impact that the FCC-ee will have on our improved knowledge of the strong force including: (i) QCD coupling determinations with permil uncertainties, (ii) ultraprecise studies of parton radiation and jet properties (ligh-quark/heavy-quark/gluon discrimination, jet substructure, etc.); and (iii) accurate scrutiny of nonperturbative QCD phenomena (color reconnection, hadronization, final-state hadron interactions,...).

Speaker: Giovanni Stagnitto (Istituto Nazionale di Fisica Nucleare)

QCDatFCC_DIS26.pdf

09:20 Classifying hadronic objects in ATLAS with ML/AI algorithms

Hadronic object reconstruction & classification is one of the most promising settings for cutting-edge machine learning and artificial intelligence algorithms at the LHC. In this contribution, highlights of ML/AI applications by ATLAS to QCD and boosted-object identification, MET reconstruction and other tasks will be presented.

Speaker: Alex Sopio (The University of Edinburgh (GB))

20260504_dis_mlai_jets.pdf

09:40 Four-jet production at electron-positron colliders at NNLO

In this talk I will present the calculation of the next-to-next-to-leading order (NNLO) correction to four-jet production at electron-positron colliders. I will discuss the details of the calculation, which is performed with the antenna subtraction technique relying on recent developments aimed at an efficient numerical implementation, and present precise phenomenological predictions for the four-jet rate.

Speaker: Matteo Marcoli (University of Durham)

Marcoli_DIS_2026.pdf

10:00 Multiplicity distributions in QCD jets and jet topics

In this talk, we will present our recent studies of the Koba–Nielsen–Olesen (KNO) scaling in multiplicity distributions within QCD jets. Specificially, We evaluate the KNO scaling functions for quark- and gluon-initiated jets by incorporating energy conservation into the Double Logarithmic Approximation (DLA). The resulting modified DLA (MDLA) expressions differ substantially from the DLA predictions and qualitatively align with the recently proposed QCD-inspired expressions, albeit with some quantitative differences. By fixing the two parameters in the MDLA expressions, we show that the inclusive charged-particle multiplicity distributions of the two leading jets in $pp$ collisions at $\sqrt{s} = 13$ TeV, measured by ATLAS over a wide jet $p_T$ range of $0.1$–$2.5$ TeV, are well described within experimental uncertainties and consistent with PYTHIA simulations. This conclusion is further supported by direct comparisons with quark- and gluon-initiated jet distributions extracted via jet topics, though the propagated uncertainties from experimental data remain sizable.

Speaker: Bin Wu (IGFAE, Universidade de Santiago de Compostela)

DIS2026_Bin_Wu.pdf

10:20 Jet energy scale and resolution calibration from hadronically decaying W boson in ttbar events in ATLAS

Jet energy scale (JES) and jet energy resolution (JER) uncertainties are among the dominant systematic uncertainties in many ATLAS measurements. After the applica- tion of simulation-based calibrations, residual differences between data and simulation are corrected using data-driven in situ techniques. In this contribution, a new in situ calibration approach exploiting tt̄ events in the single-lepton decay channel is presented. The method uses events in which one of the W bosons from top-quark decay decays hadronically into two jets, allowing the reconstruction of the W -boson invariant mass from the measured jet four-momenta. A forward-folding procedure is employed to generate template distributions of the reconstructed W -boson mass under different assumptions of the JES or JER. The mean (width) of these templates is then compared to the mean (width) of the mass distribution observed in data to extract optimal JES (JER) correction. Results obtained with this technique using the full Run 2 dataset and Run 3 data collected in 2022 and 2023 are presented. The method will be combined with other in situ calibration techniques to further improve the JES and JER precision in ATLAS.

Speaker: Adriana Dohnalová (Comenius University (SK))

DIS_JESfromWmass.pdf

10:30 Open discussion

09:00 → 10:50 WG5 Spin and 3D-structure

Convener: Matteo Cerutti

09:00 Update on transverse-spin azimuthal asymmetries in single-hadron SIDIS on transversely polarised deuterons at COMPASS

The COMPASS experiment at CERN has carried out an extensive SIDIS programme using a high-energy muon beam and polarised targets to investigate the transverse spin structure of the nucleon. In 2022, COMPASS collected data with a 160 GeV/$c$ muon beam and a transversely polarised deuteron target, complementing earlier measurements performed with a transversely polarised proton target. In SIDIS, the transverse-spin structure of the nucleon manifests itself through eight target-transverse-spin-dependent azimuthal asymmetries, providing access to different transverse-momentum-dependent parton distribution functions that encode distinct correlations between the parton transverse momentum, the nucleon transverse spin, and the parton spin. COMPASS extracts all eight asymmetries simultaneously from the same data set. We present recent updates on transverse-spin-dependent azimuthal asymmetries in single-hadron production, with particular emphasis on the Collins and Sivers effects. Together with the proton data, these results provide a comprehensive COMPASS data set on transverse-spin effects in SIDIS and offer essential input for global analyses.

Speaker: Artur Hoghmrtsyan (A. I. Alikhanyan National Laboratory)

DIS2026_AH.pdf

09:20 Update of transverse-spin azimuthal asymmetries for $K^0$ production in SIDIS

Transverse-spin-dependent azimuthal asymmetries in semi-inclusive deep-inelastic scattering (SIDIS) provide access to transverse-momentum-dependent parton distributions and fragmentation functions. In 2022, COMPASS collected SIDIS data with a 160 GeV/$c$ muon beam and a transversely polarised deuteron target, complementing the earlier COMPASS measurements on the proton. We present an update of transverse-spin azimuthal asymmetries for $K^0$ production, with emphasis on the Collins and Sivers modulations. Owing to the strange-quark content of the final state, these measurements offer new inputs for flavour separation and the study of spin–momentum correlations in the nucleon. The results pave the way for identified-hadron analyses using the 2022 deuteron data set.

Speaker: Siranush Asatryan (A. I. Alikhanyan National Science Laboratory)

Asatryan_DIS2026.pdf

09:30 Exploring the Deep Infrared Behavior of QCD through Transverse Momentum Dependent Distributions

Transverse Momentum Dependent (TMD) parton densities are well-defined QCD operators, however their determination remains challenging due to the dominance of non-perturbative effects at low energy scales. As a consequence, the impact of phenomenological modeling is difficult to control and may lead to a misinterpretation of the information carried by experimental data.
In this talk, the most commonly adopted strategies are reviewed and critically analyzed, and a novel approach based on analytic resummation is proposed. Within this framework, the non-perturbative structure of hadrons is traced back to more fundamental properties of QCD, such as the infrared behavior of the strong coupling and of the collinear parton densities.

Speaker: Andrea Simonelli (Istituto Nazionale di Fisica Nucleare)

DIS26_WG5_Simonelli.pdf

09:50 The Drell-Yan structure functions in $k_T$ factorization

We study the Drell-Yan structure functions in $Z^0$ boson production within the $k_T$ factorization framework, with particular emphasis on the Lam-Tung relation. The NNLO predictions in collinear perturbative QCD underestimate the ATLAS measurement of the Lam-Tung structure function. We investigate impact of parton transverse momenta on description of this observable and the other Drell-Yan structure functions. We take into account the contribution from the scattering of two off-shell gluons and from the scattering of a valence quark and an off-shell gluon, both evaluated at the tree level. Using several gluon transverse momentum dependent distribution (TMD) models, we compute the five non-vanishing Drell-Yan structure functions as a function of the dilepton transverse momentum and compare our results with the ATLAS data. We show that the structure functions strongly discriminate between the TMD models

Speaker: Jan Ferdyan (Jagiellonian University)

DIS2026_Ferdyan.pdf

10:10 Low-invariant-mass Drell–Yan transverse-momentum spectra: resummation and non-perturbative effects

In this talk, we present a detailed study of low-invariant-mass Drell–Yan data over the full transverse-momentum spectrum. Our predictions consistently combine small-$q_T$ resummation up to N$^4$LL accuracy with fixed-order calculations at NNLO. In the very low-$q_T$ region, non-perturbative effects become relevant and are modeled through a minimal non-perturbative form factor. The parameters of this model are fitted to experimental data and are directly related to the non-perturbative behavior of transverse-momentum–dependent parton distributions (TMDs) and of the Collins–Soper kernel.

Speaker: Lorenzo Rossi (Istituto Nazionale di Fisica Nucleare)

DIS_2026_Rossi.pdf

10:30 TMD evolution and intrinsic transverse momentum in Monte Carlo generators

The parton branching (PB) method allows using TMD evolution with standard Monte Carlo event generators, replacing the current approximate treatment of initial state radiation with a rigorous prediction from first principles. A key parameter of PB is the intrinsic $k_\mathrm T$, which governs the low-scale behaviour of the TMD. In its first extraction from collider data, tensions appeared between experiments. We discuss their origin and consequences on the extraction of TMD parameters from high-energy collider data.

Speaker: Louis Moureaux (Universität Hamburg)

Moureaux_PB_TMD_DIS_2026.pdf

09:00 → 10:30 WG6 Current upgrades and future experiments

Convener: Boxing Gou (Institute of Modern Physics, CAS)

09:00 Commissioning the sPHENIX detector with proton and nuclear beams

The sPHENIX experiment is a next-generation collider detector at RHIC designed for rare jet and heavy flavor probes of the Quark-Gluon Plasma and polarized proton-proton collisions. sPHENIX includes large-acceptance electromagnetic and hadronic calorimetry, the latter of which for the first time at RHIC, as well as a four-subsystem precision tracking system comprising a MAPS-based silicon pixel detector, a fast silicon strip detector, a compact time projection chamber, and a micromegas-based outer tracker. The trackers can be read out in both triggered and streaming readout modes, allowing for the recording of large unbiased datasets for open heavy flavor, a unique capability at RHIC. The experiment further comprises a series of forward/global detectors, and a Level-1 trigger and data-acquisition system. sPHENIX was successfully commissioned with proton and gold beams during Runs 23 and 24. This talk describes the commissioning process, including unexpected challenges, the preparation of each subsystem for physics data-taking, and lessons learned for the nuclear physics community.

Speaker: Charles Hughes (Lehigh University)

Commissioning_sPHENX_C_Hughes_03_25_26_draft6.pdf

09:20 Accelerating event generation for the HL-LHC and future collider programmes

Significant computing resources are devoted to event generation for the Large Hadron Collider (LHC), with projected demands for the High-Luminosity LHC phases expected to increase substantially and go beyond the forecasted pledged resources. At the same time, High Performance Compute (HPC) clusters provide major compute resources which in many cases rely on the deployed GPU hardware.

Madgraph5_aMC@NLO and Sherpa/Pepper are parton-level event generator projects which recently have invested into hardware acceleration via offloading onto GPUs and CPU vector instructions. We present the current status of the projects, focussing on their CPU/GPU performance, scaling behaviour on modern HPC platforms, and their applicability to the production of computationally expensive background samples for LHC analyses. We further discuss recent developments enabling improved physics reach, including machine-learning-optimised phase-space integration using Normalizing Flow models, progress towards hardware-accelerated higher-order calculations, and physics-driven improvements to numerical stability in infrared-sensitive regions.

These advances illustrate how next-generation event generation can meet the combined challenges of precision, scalability, and sustainability for the HL-LHC and future collider experiments.

Speaker: Enrico Bothmann (CERN)

bothmann-2026-dis-conference.pdf

09:40 Tensor Structure Functions of the Deuteron in SIDIS Experiments

The deuteron has a unique feature called tensor polarization, which cannot be obtained by simply combining of the proton and neutron properties and provides access to new tensor structure functions that reflect genuine nuclear effects arising from QCD dynamics, showing how quarks and gluons are modified by binding and spin correlations in a spin-1 nucleus. These functions provide a three-dimensional picture of how quark momentum and spin are distributed inside the deuteron. Recent advances in polarized target technology now allow high tensor polarization, making such measurements feasible for the first time with good precision. This talk discusses how semi-inclusive deep inelastic scattering (SIDIS) on a tensor polarized deuteron can be used to study the internal structure of a spin-1 nucleus. By detecting both the scattered electron and a produced hadron, SIDIS provides access to the three-dimensional momentum structure of quarks, including their longitudinal and transverse motion. We describe the experimental strategy at Jefferson lab and show how SIDIS measurements of a tensor polarized deuteron open a new window into the dynamics of quarks inside nuclei.

Speaker: Hector Almanzor Chinchay Espino (University of New Hampshire)

DIS2026_Hector_Chinchay_updated.pdf

10:00 The G-RWELL Endcap Tracker of the ePIC Experiment

The ePIC experiment will be the first detector of the future Electron-Ion Collider (EIC), at Brookhaven National Laboratory (BNL) by 2035.
The collisions between EIC’s polarized beams will allow us to probe nuclei and nucleons with unprecedented precision, and thus to gain access to some of the main open issues in nuclear physics: the source of the proton spin, the origin of mass in nucleons, the inner workings of confinement, and gluon saturation at high energy.
To pursue these ambitious physics goals, ePIC will deploy an array of innovative detector technologies within the compact and hermetic design of its asymmetric central detector.
The MPGD Endcap Tracker (ECT), complementing the tracking capabilities of the large central Silicon Vertex Tracker (SVT) in the high pseudorapidity regions, will consist of four disks based on the hybrid G-RWELL technology, GEM enhanced μ-RWELL detectors.
Designed to maximize acceptance and minimize material budget in the active regions, the ECT aims to achieve 150 μm spatial resolution and better than 20 ns time resolution, conserving performance for inclined tracks through the implementation of advanced μTPC reconstruction algorithms.
This contribution will focus on the preliminary design of ePIC’s MPGD endcap tracker, highlighting the extensive R&D effort towards the fabrication of its first full-size engineering test article and its validation with muon and pion beams during the 2025 test beam campaign.

Speaker: Stefano Gramigna (Istituto Nazionale di Fisica Nucleare)

2026-05-07_dis2026_the_g-rwell_endcap_tracker_of_the_epic_experiment_rev3.pdf

10:20 Higgs physics at the Muon Collider with a detailed detector simulation

This contribution explores the physics potential of a future muon collider operating at a center-of-mass energy of √s = 10 TeV for precision studies in the Higgs sector. Using a detailed detector simulation that incorporates the dominant sources of machine-induced background, the expected sensitivity to key Higgs processes is evaluated. These include measurements of the production cross sections for single Higgs production via vector boson fusion and double-Higgs production.
A central focus of the study is the determination of the Higgs boson trilinear self-coupling, a fundamental parameter for probing the structure of the Higgs potential and the nature of electroweak symmetry breaking. The analysis is performed within the framework of the MUSIC (MUon System for Interesting Collisions) detector concept, specifically optimized for the challenging muon collider environment, and assumes an integrated luminosity of 10 ab⁻¹ collected over five years of operation. The results highlight the exceptional potential of a multi-TeV muon collider to explore the Higgs sector with a level of precision unmatched by any other proposed future collider within a comparable timeframe.

Speaker: Imran Raghib Xxx (Istituto Nazionale di Fisica Nucleare)

MuCol.pdf

09:20 → 10:45 WG2 Small-x, diffraction and vector mesons

Convener: Jani Penttala (UCLA)

09:20 Non-eikonal corrections to dijet production in DIS

We study non-eikonal effects on dijet production in nuclear DIS at small x, working within the Color Glass Condensate. We include those power-supressed corrections in the high-energy limit coming from the relaxation of the shockwave approximation, while neglecting transverse components of the target fields and their dynamics. With this approximation we provide, to all orders in the length of the target, general results for the cross section by using the path-integral formalism employed in jet quenching to write the in-medium propagators of the partons. In addition, we use a specific model for the target average of Wilson lines, the harmonic oscillator approximation equivalent to the Golec-Biernat--Wüsthoff model, to expand the result order by order in the eikonal series and take the correlation limit, in order to check the results with those existing in the literature.

Speaker: Adrián Romero González (IGFAE - Universidade de Santiago de Compostela)

Presentation DIS.pdf

09:40 Constraining Proton Spin at Small Bjorken $x$ with Valence Quark Model

We apply the valence quark model with corrections coming from gluon emissions to constrain the moderate-energy behavior of the polarized dipole amplitudes responsible for the quark and gluon helicity inside the proton at small Bjorken $x$. Our model radically reduces the number of free parameters associated with the moderate-energy initial conditions to the small-$x$ helicity evolution, ultimately allowing us to determine the quark and gluon helicity inside the proton with much smaller uncertainties, compared to similar analyses employing the conventional Born-inspired initial condition. The remaining free parameters from the valence quark model are constrained via a global analysis to the available polarized small-$x$ deep inelastic scattering data, akin to contemporary works within the Jefferson Lab Angular Momentum (JAM) framework. A good description of the world data is obtained with only 8 free parameters, which are are tightly constrained by the data, allowing us to predict the proton polarized structure function, $g_1^p$, to be negative at small $x$. Furthermore, we obtain the small-$x$ quark and gluon spins to give a contribution,
$$\int_{10^{-5}}^{0.1} dx \left(\frac{1}{2}\Delta\Sigma + \Delta G\right) = 0.63 \pm 0.10\;\;\text{or}\;\;1.35\pm 0.16$$
to the proton spin, depending on the specific running coupling prescription employed.

Speaker: Yossathorn Tawabutr (Chulalongkorn University)

VQTalk_DIS2026_Tawabutr.pdf

10:00 High-Energy DIS Beyond the Eikonal Approximation

Deep-inelastic scattering at small Bjorken-$x$ is best studied in the dipole model, where the virtual photon emitted by the lepton projectile fluctuates into a quark--antiquark pair that propagates through the dense hadronic target. In this framework, the cross section is given as a convolution of an impact factor and target matrix elements of Wilson lines along nearly lightlike trajectories. The kinematic reach of the Electron--Ion Collider requires a formulation of the shock-wave formalism up to sub-eikonal accuracy. Moreover, the eikonal formulation of the dipole model is spin-blind. Consequently, helicity-dependent observables---most notably the polarized structure function
$g_1(x, Q^2)$---require a systematic inclusion of sub-eikonal interactions. Despite the efforts over the last few years from various collaborations, a complete understanding of the effect of sub-eikonal corrections on the DIS cross section has not yet been settled.

In this talk, I will present a momentum-space formulation of high-energy DIS beyond the eikonal approximation. The formalism is suitable for the phenomenology of future polarized and unpolarized measurements at the Electron--Ion Collider. Building on quark and gluon propagators in a shock-wave background computed to sub-eikonal accuracy in my previous work, I derive the corresponding momentum-space Feynman rules and compute the sub-eikonal corrections to the DIS cross section for polarized and unpolarized structure functions. To this end, I isolate the operator structures that generate helicity sensitivity at small-$x$ and provide a direct bridge between the sub-eikonal high-energy OPE and momentum-space DIS for polarized and unpolarized structure functions.

Speaker: Giovanni Antonio Chirilli (National Centre for Nuclear Research (NCBJ), Warsaw)

DIS2026-Bologna_chirilli_6may26.pdf

10:20 Next-to-Leading Order corrections to the Next-to-Eikonal DIS structure functions

We present next-to-leading order (NLO) corrections to next-to-eikonal (NEik) quark background contributions to DIS structure functions. Among NEik corrections, $t$-channel quark exchanges provide the lowest order contributions in $\alpha_s$, and can be represented as insertions of the quark background field of the target. At NLO, we compute NEik
corrections induced by both quark and gluon background fields, and suppressed by an explicit factor of $\alpha_s$. We show that the NLO corrections to the NEik longitudinal structure function are finite, while those to the NEik transverse structure function exhibit rapidity and UV divergences. These divergences are analyzed, and the finite contributions are extracted.

Speaker: Jules Favrel (National Centre for Nuclear Research (NCBJ), Warsaw, PL)

JFAVREL_DIS2026.pdf

10:45 → 11:00 Coffee break - available from 10:30 to 11:30

11:00 → 13:10 WG1 Structure functions and parton densities

Convener: Dr Francesco Giuli (Istituto Nazionale di Fisica Nucleare)

11:00 Proton structure at the LHC with neural simulation-based inference

The precise determination of the parton distribution functions (PDFs) of the proton is an essential ingredient for LHC analyses, including the upcoming High-Luminosity upgrade. PDFs are determined from a global scattering of hard scattering data taking as input unfolded low-dimensional binned cross- sections. In this work we demonstrate the feasibility of deploying neural simulation-based inference (NSBI) to constrain the proton PDFs from unbinned, high-dimensional, detector level observables taking into account all relevant experimental and theoretical systematic uncertainties. We develop procedures that allows for a detailed account of systematic uncertainties in the unbinned modeling of the high-dimensional data set and how that interplays with the PDF extraction. Adopting as proof-of-concept the determination of the large-x gluon PDFs from top quark pair production, preliminary results with our pipeline demonstrate significant sensitivity improvements as compared for traditional low-dimensional binned analyses.

Speaker: Robert Schoefbeck

26-05-07 DIS2026 SBI-PDF.pdf

26-05-07 DIS2026 SBI-PDF.pptx

11:20 Asymmetric soft resummation of Semi-Inclusive Deep Inelastic scattering

We derive threshold resummation of semi-inclusive deep-inelastic scattering (SIDIS), by building upon previous results by some of us for the resummation of the Drell-Yan process at fixed rapidity, which is related to SIDIS by crossing. We consider both a double-soft limit, in which both the Bjorken and the fragmentation scaling variables tend to their threshold value, and single soft limits in which either of them does. We show that in the former limit only soft radiation contributes, and in the latter limit only collinear radiation, and we derive resummed expressions for the coefficient functions in all cases. We determine explicitly resummation coefficients in the nonsinglet channel up to next-to-next-to-leading log by comparing to recent fixed next-to-next-to-leading order results. Expanding out the single-soft resummation we reproduce recent next-to-leading power results.

Speaker: Francesco Ventola (University of Hamburg)

Asymmetric_soft_resum_SIDIS.pdf

11:40 Model-Independent Determination of Proton Structure Functions at the Electron–Ion Collider

We investigate the feasibility of a model-independent extraction of the proton structure functions $F_2$, $F_L$ and $xF_3$ at the future Electron-Ion Collider (EIC). The method relies on measurements of the reduced cross section at multiple beam energy configurations, corresponding to different center-of-mass energies. We study the impact of datasets composed of various combinations of beam configurations that are expected to be achievable at the EIC. Using five nominal beam-energy configurations, we demonstrate that a simultaneous extraction of all three structure functions is possible. The precision is significantly improved by the inclusion of additional configurations. The contribution of $xF_3$ becomes significant at $Q^{2} \sim 100$ GeV$^{2}$ and high Bjorken-$x$. Assuming $xF_3 = 0$ in this kinematic regime results in a measurable bias in the extracted $F_L$, reflecting the intertwined dependence of the reduced cross section on these structure functions. These findings emphasize the importance of multi-energy datasets and of including $xF_3$ in the extraction of the proton structure functions.

Speaker: Javier Jiménez-López

DIS2026_structure_functions_EIC.pdf

12:00 Inclusive electron-proton measurement prospects in the Electron-Ion Collider early science stage

We explore the potential for extracting proton structure functions, proton parton density functions (PDFs), and the strong coupling $\alpha_s(M_z^2)$, using early science data from the future Electron-Ion Collider (EIC), both standalone, and in combination with HERA data. Different scenarios are considered in which samples with modest luminosity are collected at either two or three EIC beam energy configurations. The Rosenbluth separation method is used to extract the proton structure functions $F_2$ and $F_L$ from simulated data in a model-independent manner, showing that $F_L$ can be extracted significantly more precisely with three centre of mass energies than with two, whilst also obtaining $F_2$ to higher precision than has been achieved previously. The inclusion of a third beam configuration is also beneficial in the extraction of the strong coupling $\alpha_s(M_z^2)$ that is obtainable with unprecedented experimental precision with the early EIC data. Additionally, the precision of the proton PDFs is improved when adding these data, especially for large values of Bjorken-$x$, for both two and three EIC beam energy configurations. These studies show that EIC data will already be a highly competitive probe of perturbative Quantum Chromodynamics within the first five years of data taking.

Speaker: Stephen Maple (University of Birmingham)

SMaple_DIS2026_v2.pdf

12:20 Toward Precision Helicity PDFs from Global DIS and SIDIS Fits with Projected EIC Measurements

We present a new global determination of the helicity-dependent parton distribution functions (PDFs) of the proton,
based on inclusive deep-inelastic scattering (DIS) and semi-inclusive DIS (SIDIS) data within a consistent
next-to-leading order (NLO) QCD framework.
In addition to existing measurements, we incorporate simulated pseudodata for the future Electron-Ion Collider (EIC),
considering two beam-energy configurations, $E_e \times E_p = 5 \times 41~\mathrm{GeV}$\textcolor{blue}{(or GeV$^2$?)} and $18 \times 275~\mathrm{GeV}$,
corresponding to an extended kinematic reach down to $x \sim 10^{-5}$.
We focus on longitudinal double-spin asymmetries $A_1^h$ for charge-separated pion and kaon production in SIDIS
off a longitudinally polarised proton target.
These projected measurements significantly improve the flavour separation of sea-quark helicity PDFs
($\Delta \bar{u}$, $\Delta \bar{d}$, $\Delta s$) and reduce the uncertainties on
both quark and gluon helicity distributions, with the largest impact at small $x$.
Polarised PDFs are extracted using a neural-network parametrisation and a Monte Carlo replica methodology to propagate
experimental uncertainties, while theoretical constraints such as positivity are imposed during the fit.
We demonstrate that the inclusion of EIC pseudodata leads to a substantially more precise determination of helicity PDFs,
with the largest impact in the small-$x$ region.
The resulting helicity-PDF sets are provided in the {\tt LHAPDF} format.

Speaker: Dr Hamzeh Khanpour (AGH University of Kraków)

Hamzeh_Khanpour_DIS2026_Polarized_PDFs_EIC.pdf

12:40 CANCELLED: FPPDF: an Open Source Tool for Extracting Parton Distribution Functions (PDFs) in the Hessian approach and its application to N3LO PDFs

We present a new public code, FPPDF, to perform global fits of parton distribution functions (PDFs). The fitting methodology follows that implemented by the MSHT collaboration, namely applying a fixed polynomial parameterisation of the PDFs and Hessian approach to error propagation, while for data and theory settings the libraries used by the NNPDF collaboration are taken. This therefore complements the already publicly available NNPDF fitting code to enable fits with both neural network and fixed polynomial PDF parameterisations to be performed by the community, with otherwise identical theoretical and experimental inputs. As a first application, we use the new code to compare the PDFs found from fits at both NNLO and aN3LO perturbative orders, but applying these two fitting approaches.
We assess the impact of the two different methodologies on the PDFs and their uncertainties, providing results that complement previous comparisons between published PDF sets at NNLO an aN3LO. We in particular find that the relative impact of going to the higher perturbative order and/or including missing higher order uncertainties is rather insensitive to which of these PDF parameterisation methodologies are used.

Speaker: Dr Juan Manuel Cruz Martinez (Universidad de Sevilla)

jcm_fppdf.pdf

11:00 → 13:00 WG3 Electro-weak physics/higgs/top and BSM: LLPs & Future Colliders

Conveners: René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

11:00 Perspectives for studies of the HET physics at the muon-hadron collider at CERN (17'+3')

We will present the Higgs-Electroweak-Top (HET) physics potential of the proposed LH$\mu$C, an anti-muon-hadron collider at CERN [1,2]. By combining multi-TeV centre-of-mass energy with high luminosity, LH$\mu$C offers excellent conditions for exploring the HET physics. In the talk, we will report benchmark inclusive cross sections for Higgs production and for key top-quark processes, and highlight the resulting opportunities for precision Higgs-coupling studies and a broad electroweak programme. This will also include a discussion of the potential for studying the high energy photon-photon interactions at the LH$\mu$C. Finally, we will shortly overview the impact of a muon-hadron collider at the FCC-hh for the HET research [3].

References:
[1] D. Akturk et al., "μLHC: Antimuon ring and HL-LHC based μ+p collider", arXiv:2506.15445.
[2] Help4CERN Collaboration, "White Paper on High Energy, High Luminosity Lepton-Hadron Colliders at CERN", in preparation.
[3] K. Cheung and Z. S. Wang, "Physics potential of a muon-proton collider", Phys. Rev. D 103 (2021) 116009, arXiv:2101.10476.

Speaker: Dr Hamzeh Khanpour (AGH University of Kraków)

Hamzeh_Khanpour_DIS2026_HET_at_LHmuC.pdf

11:20 Probing light-quark dipole operators with nucleon energy correlators (17'+3')

We propose nucleon energy correlators (NECs) as a novel framework to probe electroweak light-quark dipole operators in deep inelastic scattering with an unpolarized nucleon. These operators encode chirality-flipping interactions, whose effects are usually quadratically suppressed in unpolarized cross sections. We construct a chiral-odd quark NEC that accesses quark transverse spin via azimuthal angle asymmetries in the energy flow of the target fragmentation region. These asymmetries serve as clean and powerful observables, enabling linear constraints on the quark dipole couplings. Unlike existing methods, our approach requires neither polarized nucleon beams nor final-state hadron identification, relying instead on fully inclusive calorimetric measurements. This work establishes one of the first applications of energy correlator observables to new physics searches and opens a promising direction for precision studies of chirality-flipping effects at electron-ion colliders.

Speaker: Yingsheng Huang (Central South University)

DIS2026.pdf

11:40 The SHiP/NA67 experiment at the ECN3 high-intensity beam facility at the CERN SPS (17'+3')

The SHiP/NA67 experiment is a general purpose intensity-frontier experiment for the search for feebly interacting GeV-scale particles and to perform neutrino physics measurements at the HI-ECN3 (high-intensity) beam facility at the CERN SPS, operated in beam-dump mode, taking full advantage of the available $4\times 10^{19}$ protons per year at 400 GeV. The Collaboration is now in the phase of TDR preparation.
The setup consists of two complementary detector systems downstream of an active muon shield: the scattering and neutrino detector (SND), consisting of a light dark matter (LDM) / neutrino target with vertexing capability. and the hidden sector decay spectrometer (HSDS), consisting of a 50 m long decay volume followed by a spectrometer, timing detector, and a PID system. BDF/SHiP offers an unprecedented sensitivity to decay and scattering signatures of various new physics models and tau neutrino physics.

Speaker: Guglielmo Frisella

DIS_conference_presentation.pdf

12:00 Results from muon object performance with the ATLAS experiment at the LHC using Run-3 proton-proton collision data

The reconstruction and precise measurement of muons are essential for a wide range of physics analyses within the ATLAS experiment at the Large Hadron Collider (LHC). During Run-3, the ATLAS Muon Spectrometer underwent major upgrades, most notably the installation of the New Small Wheel system, designed to improve tracking and triggering performance in the forward region. Assessing the performance of these new detectors with proton–proton collision data at a center-of-mass energy of 13.6 TeV is therefore a crucial step for ensuring the accuracy and reliability of physics results. Using well-known di-muon resonances, we provide a detailed evaluation of muon reconstruction, identification, and isolation efficiencies, as well as momentum scale and resolution. State-of-the-art techniques developed for Run-3 allow us to characterize the detector response with unprecedented precision. This contribution presents the latest results on muon performance, highlighting the impact of the recent upgrades on ATLAS physics capabilities.

Speaker: Volker Austrup (University of Manchester)

dis2026_atlas_muon_performance.pdf

12:20 Displaced Muons in CMS: Performance and Applications in LLP Physics (17'+3')

Several beyond standard model theories hypothesize the existence of long-lived particles (LLP) that have macroscopic decay lengths and thus can travel a measurable distance in the CMS detector before decaying. Displacement from a few hundred micrometers to several meters allows probing a wide range of models predicting LLP decaying to muons. To track with high precision muons that are displaced from the collision point, the CMS collaboration has developed specific objects called “displaced muons”, reconstructed without making any assumption on the position where muon track originates. Precise knowledge of the performance of displaced muons reconstruction at high levels of displacement, both for simulation and data, is a key ingredient for analyses searching for LLPs decaying into muons. Analyses in this sector are expected to benefit significantly from both the increased statistics of Run 3 and the improvements coming from the usage of displaced muon objects and triggers. This talk will motivate the need for displaced muon objects, report on updates on their performance and highlight their relevance for physics analyses, such as an inclusive search for long-lived exotic particles decaying to final states with a pair of muons.

Speaker: Marco Cruciani (University of Bologna and INFN)

DIS2026_Cruciani.pdf

12:40 Probing Electroweak Interactions and Beyond the Standard Model Physics at Belle II (17'+3')

The Belle II experiment at the SuperKEKB e⁺e⁻ collider has collected over 575 fb⁻¹ of data since 2019. Operating in a low-background environment with well-constrained kinematics, Belle II provides exceptional sensitivity to electroweak processes and searches for physics beyond the Standard Model. This talk will present recent Belle II results including the first evidence for B⁺→K⁺νν̄ decay and searches for other b→sνν̄ transitions, measurements of CP violation in heavy-quark and τ-lepton systems, and precise determinations of fundamental Standard Model parameters. Future prospects with larger datasets and planned detector upgrades will also be outlined.

Speaker: Angelo Di Canto (Brookhaven National Laboratory)

2026_DIS.pdf

11:00 → 12:45 WG6 Current upgrades and future experiments

Convener: Lesya Shchutska (EPFL)

11:00 Transition Radiation Detector Upgrade for the GlueX-III Charmonium Program

Precision electron identification is a critical challenge in electro/photo-production and deep-inelastic scattering experiments with large hadronic backgrounds. The GlueX-III experiment, planned to run at Jefferson Lab for 2027-2028, will significantly enhance the laboratory’s capability to explore charmonium production near threshold and related aspects of Quantum Chromodynamics in the non-perturbative regime. This talk will present the physics motivation for GlueX-III’s charmonium program, with emphasis on J/ψ photoproduction near threshold, its sensitivity to gluonic structure of nucleons, and the critical role of efficient electron-hadron separation for rejecting hadronic backgrounds and isolating rare dielectron final states. A central upgrade for GlueX-III, approved by the Jefferson Lab Program Advisory Committee in 2025, is a large-scale triple-GEM Transition Radiation Detector (TRD) optimized for electron identification and pion suppression in the hadron-rich environment of fixed-target photoproduction. We will describe the design, construction, and in-beam performance of a 720x528 mm2 triple-GEM-TRD prototype tested in the existing GlueX-II experimental acceptance during the 2025 run, including detector stability, timing performance, and transition radiation cluster identification. The detector’s integration with the GlueX tracking system is anticipated to improve the overall momentum resolution of the experiment. Its projected impact on signal purity and systematic uncertainties of the cross-section measurement will also be discussed. Simulation studies on detector performance related to electron/pion separation will be presented. Reconstruction of dielectron final states using data collected with the detector during the GlueX-II run will also be demonstrated. This talk will outline how the development and use of a modern TRD technology in a high-background environment at Jefferson Lab stands to directly inform detector design choices as a future upgrade path for the Electron-Ion Collider (EIC). There, precise electron identification amidst vast hadronic backgrounds and high rates will be essential for a broad expanse of physics measurements. The detector simulations can also be readily applied to the Electron-Ion Collider environment, to better demonstrate the advantages of a GEM-based TRD for the planned EIC physics program.

Speaker: Lauren Kasper (Vanderbilt University)

LaurenKasper_DIS_May_2026.pdf

11:20 Calibration and performance of the ATLAS Tile Calorimeter

The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The scintillators are read-out by the wavelength shifting fibres coupled to the photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped, digitized by sampling the signal every 25 ns and stored on detector until a trigger decision is received. The TileCal front-end electronics reads out the signals produced by about 10000 channels measuring energies ranging from about 30 MeV to about 2 TeV. Each stage of the signal production from scintillation light to the signal reconstruction is monitored and calibrated. The calorimeter time resolution has been studied with multi-jet events. High-momentum isolated muons have been used to study and validate the electromagnetic scale, while hadronic response has been probed with isolated hadrons. This contribution will present recent performance results, including the calibration, stability, absolute energy scale, uniformity and time resolution.

Speaker: Martina Cucinotta

DIS2026_Cucinotta.pdf

11:28 ATLAS Tile Calorimeter Phase-II Upgrade: Current Status and its Demonstrator Module

The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter that covers the central region of the ATLAS experiment at the Large Hadron Collider (LHC). The LHC will undergo a series of upgrades leading to the High-Luminosity LHC (HL-LHC). The TileCal Phase-II Upgrade will accommodate the detector readout electronics to meet the challenges of a 1 MHz trigger rate, higher ambient radiation levels, and increased pile-up conditions. The TileCal Phase-II upgrade project has undertaken an extensive R&D program. The Demonstrator Phase-II Upgrade module was built in 2014 with the upgraded readout electronics and backward compatibility with the present ATLAS Trigger and Data Acquisition system. Its electronics were evaluated during seven test beam campaigns using the CERN SPS fixed target facility. To gain more experience with collision data, the Demonstrator Phase-II Upgrade module was inserted into the ATLAS experiment in 2019. This module operates under real detector conditions during Run-3 (2022–2026). This contribution describes the hardware and software upgrades of the Demonstrator Phase-II Upgrade module and discusses the operations findings from this module within ATLAS, as well as the latest performance results.

Speaker: Sonakshi Ahuja (IFIC-CSIC (UV))

DIS2026_Sonakshi .pdf

11:48 Probing Radiation Damage in SiPMs with Emission Microscopy

Silicon sensors are widely employed in modern physics experiments in both tracking detectors and photo-detection systems. Silicon photomultipliers (SiPMs) are increasingly adopted for their excellent photon detection efficiency, fast timing, scalability, and insensitivity to magnetic fields. A first application of SiPMs for single-photon detection in a collider experiment will be for the dual-radiator (dRICH) detector of the ePIC experiment at the future Electron-Ion Collider (EIC). The dRICH photodetector will cover ~3 m$^2$ with 3x3 mm$^2$ pixels, for a total of more than 300000 readout channels and will be the first application of SiPMs for single-photon detection in a collider experiment. The SiPMs excellent performance is challenged by radiation damage arising from the high particle fluxes typical of hadron collider environments. Ionising and non-ionising radiation introduces defects in the silicon lattice, which manifest as increased dark count rate, ultimately degrading single-photon sensitivity.

As radiation-induced defects act as generation-recombination centres in the silicon lattice, light is emitted from these defects and can be spotted taking pictures of the device with a high-performance camera. We complement the traditional electrical characterization of SiPMs after irradiation with an optical characterization of the sensors, using emission microscopy to directly visualise radiation-induced defects in the silicon lattice and their evolution with detector operational parameters (temperature and bias voltage), irradiation damage, and recovery from annealing. This combined methodology provides deeper insight into the nature and localisation of the damage, offering a more comprehensive understanding of its impact on SiPMs performance.

In this talk, the microscope setup and the first results will be presented. Pictures taken before and after irradiation with protons and neutrons at a fluency of ~10$^9$ n$_{eq}$/cm$^2$, and after annealing cycles, show the evolution of the defects in the Hamamatsu SiPM sensors under study.

Speaker: Ludovica Rainero

DIS presentation on SiPM - L-Rainero.pdf

11:15 → 13:00 WG2 Small-x, diffraction and vector mesons

Convener: Jani Penttala (UCLA)

11:15 Next-to-leading power gluon TMDs from back-to-back DIS dijets at next-to-eikonal accuracy at low x

We consider dijet production in deep inelastic scattering at small x, on a purely gluonic unpolarized target. Starting from earlier results obtained at next-to-eikonal accuracy in the high-energy limit, we perform the expansion in the back-to-back dijet limit, at next-to-leading power (NLP) accuracy. We rewrite our results in the language of transverse-momentum-dependent (TMD) factorization, in terms of leading power and NLP TMD gluon distributions (gluon TMDs).
In particular, we focus on the contribution to the cross section of NLP gluon TMDs corresponding to correlators of three gluon field strength tensors. Their proper derivation from the low x formalism requires to go beyond the semi-classical approximation of the CGC, which amounts to keeping track of the ordering of fields as quantum operators.
This study allows us to improve our understanding of the interplay between the TMD and low x approaches, by including the first power corrections with respect to the back-to-back jets limit as well as with respect to the eikonal limit.

Speakers: Kacper Goslawski (National Centre for Nuclear Research, Warsaw), jules Favrel (National Centre for Nuclear Reseach, Warsaw, PL)

Goslawski_Conference_Presentation.pdf

11:35 One-loop renormalization of the quark TMD in the projectile light-cone gauge

We use the background field formalism to calculate NLO corrections to a quark transverse momentum dependent parton distribution function (TMD) in the projectile light-cone gauge, i.e. $A^+=0$ for a left-moving target.
We calculate the full result using two different ways, corresponding to different prescriptions for handling the light-cone singularity: the Mandelstam–Leibbrandt and a family of prescriptions including principal value, retarded, and advanced prescriptions.
From the one-loop renormalization of the quark TMD, we obtain the Collins-Soper-Sterman (CSS) evolution equations. Remarkably, different prescriptions for the light-cone gauge will yield very different results for individual diagrams, but ultimately lead to the same final result.

The calculation is a continuation of similar work in the target light-cone gauge [1].
The projectile light-cone gauge is widely used in calculations within the gluon saturation regime. Our work therefore opens a way to understanding the connections between the TMD and Colour Glass Condensate (CGC) approaches within the same framework.

[1] T. Altinoluk, G. Beuf, J. Jalilian-Marian, arXiv:2505.20467 [hep-ph]

Speaker: Mirja Tevio (National Center for Nuclear Research (NCBJ), Warsaw)

tevioDIS26.pdf

11:55 Sudakov effects vs saturation dynamics in SIDIS at small x

Single inclusive hadron production in Deep Inelastic Scattering (SIDIS) is one of the most promising processes in which to look for signatures of color glass condensate (CGC), a dense state of gluons in a proton/nucleus that is believed to exist at small $x$. While there have been strong hints of CGC dynamics observed at HERA, RHIC and the LHC, an unambiguous interpretation has eluded the community due to presence of several important non-CGC effects. One of the most important such effects is Sudakov suppression due to radiation of soft gluons. Here we present our calculation of Sudakov double logs in SIDIS and report on the progress made toward calculation of Sudakov single logs, a completion of which would go a long way toward establishing, quantitatively and for the first time, the relative significance of Sudakov effects vs Saturation dynamics in different kinematics at the future EIC.

Based on PRD 110 (2024) 9, 094056 and in progress

Speaker: Jamal Jalilian-Marian (Baruch College)

dis-05-2026.pdf

12:15 Connecting Regge Factorization and Collins–Soper Evolution

The relationship between Regge factorization of amplitudes and the Collins–Soper–Sterman factorization of hadronic cross sections is explored. Aiming at a unified description of the treatment of rapidity divergences and the high-energy asymptotic behavior of scattering amplitudes, novel insights into the extension of $k_T$-factorization beyond leading-log (LL) accuracy are revealed. In particular, an intriguing connection emerges between the Collins–Soper kernel, characteristic of transverse-momentum-dependent factorization, and the Regge trajectory.

Speaker: Andrea Simonelli (Istituto Nazionale di Fisica Nucleare)

DIS26_WG2_Simonelli.pdf

12:35 Jet Definition and Transverse-Momentum–Dependent Factorization in Semi-inclusive Deep-Inelastic Scattering

Semi-inclusive deep inelastic scattering (SIDIS) with a hadron measured in the final state is a well-established observable to probe the three-dimensional momentum structure of nucleons and nuclei, in particular at small Bjorken $x$ where the cross-section factorizes in terms of a sea quark transverse momentum (TMD) distribution [1]. However, to extract TMDs from hadron measurements, one needs precise knowledge of the corresponding TMD fragmentation functions into hadron. An alternative is to consider the production of jets, which provide a clean, pQCD-controlled final state. Understanding how TMD factorization applies to jets in SIDIS, however, is far from straightforward.

In this talk, based on [2], we address this question in the small-$x$ limit of SIDIS. Using the colour dipole picture of Deep Inelastic Scattering and the Colour Glass Condensate effective theory, we study semi-inclusive jet production in DIS in the regime where the photon virtuality $Q^2$ is much larger than the jet transverse momentum squared $P_\perp^2$. We show that physically meaningful jet definitions are those where the effective jet axis is set by the virtuality of the struck quark rather than its transverse momentum. For such definitions, the next-to-leading order (NLO) cross-section factorizes in terms of the sea quark TMD, which obeys universal Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) and Collins-Soper-Sterman (CSS) evolution.

Our results provide a solid theoretical framework for performing and interpreting jet measurements in SIDIS at the future EIC and for mapping the TMD parton distributions of nuclei at high energies.

[1] Marquet, Xiao, Yuan, Phys.Lett.B 682 (2009)
[2] Caucal, Iancu, Mueller, Yuan, Phys.Rev.Lett. 134 (2025) 6, 6

Speaker: Paul Caucal (SUBATECH, Nantes Université, IN2P3/CNRS)

caucal_DIS2026-jetdef.pdf

11:15 → 13:00 WG4 QCD with Heavy flavours and Hadronic Final States

11:15 Multi-Particle Final State in DIS on Nuclei with BeAGLE++

BeAGLE (Benchmark eA Generator for Leptoproduction) is the primary event generator currently used to simulate deep inelastic scattering on nuclei (e+A) for the upcoming Electron-Ion Collider (EIC) in the U.S. It plays a central role in advancing our understanding of key nuclear physics processes, informing detector design, and guiding the integration requirements for interaction regions. As the principal simulation tool used by the ePIC collaboration, BeAGLE is expected to be pivotal for the physics case and engineering of the second IR. However, BeAGLE’s legacy FORTRAN codebase presents significant challenges for modern development, extensibility, and long-term support. To overcome these limitations, we have initiated a comprehensive rewrite of BeAGLE in C++, resulting in BeAGLE++, a modern, modular, and extensible event generator designed to meet the evolving demands of the EIC physics program.
In this talk, I will present the first release of BeAGLE++, highlighting its architectural improvements and enhanced physics capabilities. Particular focus will be given to simulations of particle production in the target fragmentation region, a key probe of final-state interactions and nuclear effects. BeAGLE++ will be essential for precision simulations, systematic studies, and data analysis workflows, providing the community with a robust and sustainable toolset ahead of EIC operations and marking a major step forward in lepton-nucleus collision modeling.

Speaker: Win Lin (Stony Brook University)

dis_win_arjun.pdf

11:35 Probing jet quenching in the QGP using inclusive and semi-inclusive charged-particle jet measurements with ALICE at the LHC

The ALICE experiment at the LHC is focused on the investigation of the Quark-Gluon Plasma (QGP), a fundamental state of matter at high temperature in which quarks and gluons are deconfined, and which is generated in heavy-ion collisions at ultra-relativistic energies. One of the key experimental signatures to explore the structure and dynamics of the QGP is ‘jet quenching’, the modification of jet structure resulting from the interaction of high-energy quarks and gluons with the plasma. The ALICE detector’s excellent particle identification and tracking performances, down to low momentum in high-density environments, enable jet-quenching measurements over a very broad phase space, including low-energy and large-radius jets that are seen to be strongly modified, providing a window into the response of the QGP to excitations.
In this talk, I will present recent measurements of inclusive charged-particle jet yield modification in Pb-Pb collisions as well as semi-inclusive measurements of charged-particle jets recoiling from a trigger hadron. These measurements utilise novel data-driven statistical approaches to subtract the large uncorrelated background present in heavy-ion collisions. Comparison to state-of-the-art theoretical calculations incorporating jet quenching effects will also be discussed.

Speaker: Marielle Chartier (University of Liverpool)

Marielle Chartier DIS2026 v3.pdf

11:55 Heavy-Flavor Studies with the ePIC Experiment at the Electron–Ion Collider

The Electron–Ion Collider (EIC) provides an unprecedented opportunity for polarized collisions. The ePIC (electron–Proton/Ion Collider) will be a general-purpose detector with good tracking and vertexing capabilities, enabling efficient reconstruction of displaced vertices. Measurements of heavy-flavor at the EIC offer a powerful probe to access a wide range of physics studies, such as testing perturbative QCD calculations, constraining gluon dynamics in nuclei from moderate to high Bjorken-$x_B$ , and studying parton fragmentation and hadronization and their expected modifications in electron–nucleus (eA) collisions.
This contribution will present the performance studies heavy-flavor hadron reconstruction, with an emphasis on physics observables in ep and eA systems. The sensitivity to charm-quark hadronization is explored through reconstruction of various charm hadrons with realistic full detector simulation. Nuclear effects are explored by studying the projected precision of the nuclear modification factor ($R_{\rm eAu}$ ) in eAu collisions. Its impact on constraining nuclear parton distribution functions, particularly those associated with the gluon density, will also be discussed. In addition, the performance studies of inclusive jet reconstruction will be presented, highlighting towards future prospects for heavy-flavor jet tagging.

Speaker: Domenico Elia (Istituto Nazionale di Fisica Nucleare)

ePIC_Jets_HF_Studies_DIS_2026.pdf

12:15 Light (Anti)Nuclei Production via Coalescence in Electron–Proton Collisions: from HERA to EIC

The production mechanisms of light nuclei, particularly the coalescence model, have become a focal point of research in collider experiments. While hadron–hadron collisions have been extensively used to study light (anti)nuclei across a broad energy spectrum, the complexity of these interactions often obscures the underlying kinematics.

Deep-inelastic scattering (DIS) systems, such as electron–proton collisions, offer a cleaner, complementary environment due to their well-defined initial state. In particular, in the forward proton fragmentation region, the production of light (anti)nuclei is highly sensitive to the proton's valence quark structure. This makes it a powerful observable for probing proton structure and testing the coalescence mechanism in a controlled lepton–hadron environment.

In this work, we present predictions for light (anti)nuclei production via the coalescence model, implemented as an afterburner in PYTHIA simulations. We study electron–proton collisions at HERA energies and explore new kinematic regimes accessible at the future Electron–Ion Collider (EIC).

Speaker: Niccolò Ciavarelli (Istituto Nazionale di Fisica Nucleare)

Ciavarelli_DIS2026.pdf

12:25 Open Discussion

11:15 → 13:00 WG5 Spin and 3D-structure

Convener: Tyler Kutz (Johannes Gutenberg University Mainz)

11:15 Transverse Spin Dependent Azimuthal Correlations of Charged hadron pairs in $p^\uparrow p$ Collisions at $\sqrt s = 200$ GeV at STAR

Transversity, $h_1^{q}(x)$, a leading twist parton distribution function, describes the transverse spin distribution of quarks in a transversely polarized proton. It is a fundamental component of nucleon spin structure and is loosely constrained by global fits. As a chiral odd function, $h_1^{q}(x)$ can only be accessed when coupled with another chiral odd partner, such as an interference fragmentation function (IFF). This coupling of $h_1^{q}(x)$ and IFF leads to a measurable azimuthal correlation asymmetry ($A_{UT}$) of hadron pairs in final states. The STAR experiment at RHIC has previously reported non-zero $A_{UT}$ for $\pi^+\pi^-$ in transversely polarized proton-proton ($p^\uparrow p$) collisions at $\sqrt{s} $ = 200, 500, and 510 GeV. Measurements of di-hadron $A_{UT}$ with other hadron species provide additional flavor sensitivity, for example, measurements with $K^+K^-$ provide access to $h_1^{q}(x)$ of strange quarks. While non-zero $A_{UT}$ has been measured for $\pi^{+}\pi^{-}$ pairs, we will present an update on the ongoing analysis of $A_{UT}$ for identified hadron pairs using the 2015 $p^{\uparrow}p$ data at $\sqrt{s} = 200$ GeV in the mid-pseudorapidity region $(|\eta|<1)$, focusing on $K^{+}K^{-}$, $K^{+}\pi^{-}$, and $\pi^{+}K^{-}$ pairs.

Speaker: Mrs Anuja khanal (Temple University)

Anuja_DIS2026.pdf

11:35 Measurement of Lambda hyperons spin correlation in pp and pPb collisions at CMS

The spin correlations of $\Lambda$ hyperons offer a direct window into QCD spin dynamic, including spin-orbit coupling, polarization transfer during hadronization, and possible local spin entanglement in the fragmentation process. With the high-statistics data collected by the CMS experiment, we present the first spin correlation results for $\Lambda\Lambda$, $\Lambda\bar{\Lambda}$ and $\bar{\Lambda}\bar{\Lambda}$ in pp collisions $\sqrt{s}= 13$ TeV and pPb collisions at $\sqrt{s_{NN}}= 8.16$ TeV as functions of spatial distance ($\Delta R = \sqrt{\Delta \eta^{2} + \Delta \phi^{2}}$) between the hyperon pairs. These high‑precision measurements provide new constraints on microscopic models of spin generation and hadronization, enabling discrimination between fragmentation and recombination mechanisms and opening a novel experimental avenue for QCD spin studies.

Speaker: Jieke Wang

DIS2026-JiekeWang-v7.pdf

11:55 Hyperon polarization in deep inelastic scattering

The string+3P0 model of spin-dependent hadronization is extended to include the production and decay of polarized spin-1/2 baryons alongside pseudoscalar and vector mesons, and it is implemented in the Pythia event generator for the simulation of deep inelastic scattering (DIS).
The model is used to investigate the spontaneous polarization of lambda, antilambda and other hyperons produced in current and target fragmentations in DIS events with an unpolarized proton target. Large effects are observed in the target fragmentation region calling for measurements feasible using available data from fixed target experimental facilities that can enlighten our understanding of the quark spin dependence of hadronization.

Speaker: Albi Kerbizi (Trieste University and INFN)

Kerbizi-DIS2026.pdf

12:15 Probing the hadronization of polarized parton at unpolarized hadron colliders

Spin-dependent fragmentation functions encode essential information on the spin transfer from partons to hadrons and are typically studied in experiments with polarized beams. In particular, the longitudinal spin transfer $G_{1L}$ remains poorly constrained. In $Z^0/W^\pm$-tagged jet production, the parity violation of weak interaction induces a longitudinal polarization of the jet. This polarization allows $G_{1L}$ to be investigated in unpolarized $pp$ and $AA$ collisions. Our results indicate that the $\Lambda$ hyperon polarization is sensitive to $G_{1L}$ and can be used to constrain this fragmentation function.
Reference: W. H. Yao, X. Li, H. Dong and S. Y. Wei, arXiv:2511.06705 [hep-ph]

Speaker: Wen-Hao Yao (Shandong University)

DIS 2026 Wen-Hao Yao.pdf

12:35 Spin-Spin entanglement in exclusive heavy quark–antiquark pair production

In recent years, growing attention has been devoted to the interface between collider physics and quantum information. A particularly intriguing direction is the exploration of quantum phenomena, such as entanglement, in high-energy scattering processes, including DIS at the EIC and ultraperipheral collisions at the LHC. In this context, we present the first study of spin--spin correlations in the exclusive production of a heavy quark--antiquark pair. We show that, in the Regge limit, the diffractive mechanism leaves a distinctive imprint on the quantum correlations of the final state: the produced $q\bar q$ pair is always entangled and exhibits a violation of the Bell--CHSH inequality.

Speaker: Michael Fucilla

Entanglement.pdf

13:00 → 14:00 IAC meeting

IAC meeting agenda

13:00 DIS 2026 IAC meeting

13:00 → 14:30 Lunch break

15:30 → 18:30 Excursion

Friday 8 May

09:00 → 10:30 Plenary 5

Convener: Néstor Armesto (Universidade de Santiago de Compostela)

09:00 The EPPS proposal and LHeC perspectives

Speakers: Jorgen D'Hondt (Nikhef), Jorgen D'Hondt (Nikhef)

09:30 EIC: physics, status and perspectives

Speaker: John Lajoie

The EIC - Physics, Status and Perspectives rev7 SPLIT.pdf

10:00 Outreach: social aspects in high energy physics

Speaker: Anja Kranjc Horvat (EPFL)

10:30 → 11:00 Coffee break

11:00 → 12:10 Plenary 6

Convener: Halina Abramowicz (Tel Aviv University)

11:00 An homage to Antonino Zichichi

Speaker: Luisa Cifarelli (Istituto Nazionale di Fisica Nucleare)

11:30 Altarelli Prize ceremony

Speaker: Fredrick Olness (SMU)

Guido-s-interview.mov

Guido-s-interview2.m4v

12:10 → 13:00 Plenary 7: Reports from Working Groups

Convener: Juan Terron Cuadrado (Universidad Autonoma de Madrid)

12:10 Report WG1: Structure Functions and Parton Densities

Speakers: Alberto Accardi (Hampton U. and Jefferson Lab), Claire Gwenlan (University of Oxford (GB)), Klaus Rabbertz (KIT)

12:35 Report WG5: Spin and 3D Structure

Speakers: Jan Matousek (Charles University, Prague), Dr Matteo Cerutti (CEA Paris-Saclay), Tyler Kutz (Johannes Gutenberg University Mainz)

13:00 → 14:15 Lunch break

14:15 → 15:55 Plenary 8: Reports from Working Groups

Convener: Marta Ruspa (Istituto Nazionale di Fisica Nucleare)

14:15 Report WG4: QCD with Heavy Flavors and Hadronic Final States

Speakers: Cynthia Hadjidakis (IJCLab/CNRS/Paris-Saclay University), Lucilla Lanza (Istituto Nazionale di Fisica Nucleare), Melissa Van Beekveld

14:40 Report WG3: Electroweak Physics and Beyond the Standard Model

Speakers: Ken Mimasu (University of Southampton), Menglin Xu, René Poncelet (IFJ PAN Krakow), Supriya Sinha (DESY)

15:05 Report WG6: Current Upgrades and Future Experiments

Speakers: Boxing Gou (Institute of Modern Physics, CAS), Domenico Elia (Istituto Nazionale di Fisica Nucleare), Lesya Shchutska (EPFL)

15:30 Report WG2: Small-x, Diffraction and Vector Mesons

Speakers: Cristovao Fernandes Vilela, Jani Penttala (UCLA), Michael Pitt (CERN)

15:55 → 17:00 Closing session

15:55 DIS2025 Best Student Talk Awards

Speaker: Francesca Bellini (Istituto Nazionale di Fisica Nucleare)

16:05 Report from the IAC

Speakers: Aharon Levy (Tel Aviv University), Paul Newman

Report-from-IAC-2026.pdf

Report-from-IAC-2026.pptx

16:20 Closing remarks

Speaker: Pietro Antonioli (Istituto Nazionale di Fisica Nucleare)