In this presentation, I will discuss selected highlights in electromagnetic hadron physics since the last edition of EINN held remotely in 2021
I give a broad overview of recent theory developments and open questions for a subset of topics discussed at this conference. The focus lies on different ways of 'imaging' the nucleon, from form factors to parton distributions.
The Muon g$-$2 experiment at Fermilab aims to measure the anomalous magnetic moment of the muon, $a_\mu = (g-2)/2$, with a final accuracy of 140 parts per billion, representing one of the most precise tests of the Standard Model. The experiment's first result from the 2018 dataset, Run 1, was published in 2021 and confirmed the previous result obtained at Brookhaven National Laboratory with a...
Over twenty years ago, in an experiment at Brookhaven National Laboratory, physicists detected what seemed to be a discrepancy between measurements of the muon’s magnetic moment and theoretical calculations of what that measurement should be, raising the tantalizing possibility of physical particles or forces as yet undiscovered. The Fermilab team has announced 2021 and then in 2023 that their...
Heavy quarkonium production serves as a powerful tool to investigate the gluonic structure of the nucleon. The latest generation of experiments being conducted at Jefferson Lab in the 12 GeV era use near-threshold J/ψ production to explore the mass structure of the nucleon. In this presentation, I will focus on both current and forthcoming experiments aimed at unraveling the proton’s gluonic...
An overview of the progress preparing the Electron-Ion Collider (EIC) for construction. The presentation addresses the EIC design requirements, conceptual design, and construction schedule. Current efforts to promote international engagement and collaboration will be described, including opportunities for contributions to the design and construction of the accelerators and collaboration on...
We present a brief report on our ongoing efforts to calculate the transverse single-nucleon spin asymmetry of single-inclusive jet production in lepton-nucleon collisions at NLO accuracy within the collinear twist-3 factorization framework. This observable can very well be measured at a future Electron-Ion Collider (EIC). Such data will give new insight into both the partonic structure of the...
The design of the electron-ion collider (EIC) at Brookhaven National Laboratory
is well underway, aiming at a peak electron-proton luminosity of 10^34 cm^-2
sec^-1. This high luminosity and wide center-of-mass energy range from 29 to
141 GeV (e-p) require innovative solutions to maximize the performance of the
machine, which makes the EIC one of the most challenging accelerator...
We present our results on transverse momentum dependent factorization and resummation at sub-leading power in Drell-Yan and semi-inclusive deep inelastic scattering. In these processes the sub-leading power contributions to the cross section enter as a kinematic power correction to the leptonic tensor, and the kinematic, intrinsic, and dynamic sub-leading contributions to the hadronic tensor....
Understanding the properties of nuclear matter and its emergence through the underlying partonic structure and dynamics of quarks and gluons requires a new experimental facility in hadronic physics known as the Electron-Ion Collider (EIC).
The EIC will address some of the most profound questions concerning the emergence of nuclear properties by precisely imaging gluons and quarks inside...
We present results for the nucleon axial and pseudoscalar form factors extrapolated at the continuum limit using three $N_f = 2 + 1 + 1$ twisted mass fermion ensembles with all quark masses tuned to their physical values. Convergence to the ground state matrix elements is assessed using multi-state fits. We study the momentum dependence of the three form factors and check the partially...
On behalf of the ePIC Collaboration
The future Electron-Ion Collider (EIC) at Brookhaven National Laboratory will collide polarized electrons with polarized proton/ions. The electron Proton and Ion Collider (ePIC) detector is being designed as the day one EIC detector. The EIC physics program requires precision tracking and particle identification (PID) capabilities that extend over a large...
In global extractions of Transverse momentum dependent (TMD) distributions, the limit of small transverse distances is constrained using the matching to collinear parton density functions (PDF). Naturally, the TMDPDFs depend on the baseline PDF set used certain features of the former might be due to the latter, rather than genuinely due to TMD behaviour f the partons. To shed light on the...
We review the current status of the nucleon's helicity PDFs. We describe
recent progress on "global" analysis of the distributions, highlighting
advances on the theoretical side especially in terms of higher-order
perturbative calculations. We discuss the relevance of these advances
for the spin program at the future EIC.
The ePIC detector is being designed as a general-purpose detector for the Electron-Ion Collider (EIC) to deliver the full physics program. One of the key challenges at the EIC is particle identification (PID), which requires excellent separation of pions, kaons, and protons over a wide phase space with significant pion/electron suppression. To address this challenge, ePIC utilises multiple...
We present results for the axial, tensor, and scalar charges of the nucleon using lattice QCD simulations of twisted mass fermions with two degenerate light, a strange, and a charm quark, with masses tuned to their physical values (physical point simulations). The axial charge is well known experimentally and therefore provides for an important benchmark of our methodology, while the scalar...
This talk will cover some of the electromagnetic calorimetry plans for the ePIC detector with a concentration on the design of the central barrel calorimeter based on the current GlueX BCAL at JLab. The requirements (as specified in the ePIC Project) include energy resolution of 10%/$\sqrt{E} \oplus (2-3)$% and electron-pion suppression great than $10^3$, which will be comfortably met by a...
The gravitational form factors (GFFs) of hadrons are related to the matrix elements of the energy-momentum tensor of QCD. In recent years, the proton and pion GFFs have been constrained for the first time from experimental measurements. We compute the quark and gluon GFFs of the pion and the nucleon in the kinematic region $0 < -t < 2~\text{GeV}^2$ on a clover improved lattice QCD ensemble...
The Mainz Energy-Recovery Superconducting Accelerator MESA, currently under construction at the Institute of Nuclear Physics at Mainz, provides the basis for precision experiments in the areas of nuclear, hadron, and particle physics. In this talk, we report on the comprehensive physics program of the three fixed-target experiments prepared for MESA: (i) MAGIX, (ii) P2, and (iii) DarkMESA....
Dark matter exploration is become a central or side topic of many experiments at particle accelerators. Even if this approach, up-to-now, has not produced evidences, it helped in setting stringent limits on the characteristics of dark matter.
In this panorama is inserted the Positron Annihilation into Dark Matter Experiment (PADME) ongoing at the Laboratori Nazionali di Frascati of INFN....
A summary of experimental measurements unveiling spin-dependent nucleon structure prior to the arrival of the Electron-Ion Collider is given. Results from fixed-target experiments at Jefferson Lab, CERN, and DESY and collider experiments from RHIC will be presented. The measurements will be discussed in the context of transverse proton or parton spin and transverse parton momenta (TMDs), and...
In the first part of the talk, I will review the recent progress on nucleon parton distributions in the global QCD analysis. In the second part, I will discuss the important role of epistemic uncertainties on PDFs in the increasingly common situation when other experimental and theoretical uncertainties are small. The AI techniques may complicate, rather than simplify, estimation of such...
In this talk, I will report on recent progress in Quantum Monte Carlo calculations of electron and neutrino interactions with nuclei in a wide range of energy and momentum transfer and their connections to current experimental efforts in fundamental symmetries and neutrino physics.
The theory of the strong force, Quantum Chromodynamics, describes the proton in terms of quarks and gluons. The proton is a bound state of two up and one down quark, but quantum theory predicts that in addition there is an infinite number of quark-antiquark pairs. Both light and heavy quarks, whose mass is respectively smaller or bigger than the proton’s, are revealed inside the proton in...
Generalized Parton Distributions (GPDs) are nowadays the object of an intense effort of research, in the perspective of understanding nucleon structure. They describe the correlations between the longitudinal momentum and the transverse spatial position of the partons inside the nucleon and they can give access to the contribution of the orbital momentum of the quarks and gluons to the nucleon...
In this contribution, I will present a recomputation of the evolution kernels of generalised parton distributions (GPDs) at one-loop accuracy for all of the three possible leading-twist polarisations: unpolarised, longitudinally polarised, and transversely/linearly polarised.
I will discuss the analytic and numerical properties of these kernels presenting a number of numerical results for...
Beam polarimetry will play an important role in meeting the goals of the planned EIC physics program. However, the EIC beam properties will make achieving the level of precision required challenging for both electron and hadron beam polarimetry.
In this talk, I will give a brief overview of the techniques used to measure electron and hadron beam polarization at high energies, and discuss...
Precise measurements of the electron-hadron cross sections are the corner stone of scientific program at the future Electron-Ion Collider, hence the high demands towards the EIC luminosity measurements – at least a 1% accuracy is required for the absolute luminosity determination and only a 0.01% uncertainty for the relative, bunch-to-bunch, luminosity measurements. As was demonstrated at HERA...
We present the first direct lattice QCD calculation of the x-dependent pion distribution amplitudes on domain wall gauge ensembles at physical pion mass. We use the large momentum effective theory to directly calculate the x-dependence of meson DAs with several recently developed self-consistent precision control methods. We perform a leading renormalon resummation to remove linear...
In this presentation, we delve into the calculation of perturbative corrections for the Deeply Virtual Compton Scattering process within a unique kinematic domain, specifically where $t \gg \Lambda^2_{\rm QCD}$, with $t$ representing the change in nucleon momentum following scattering. Working within this unconventional domain necessitated a distinctive approach, particularly dealing with...
The investigation of nucleon elastic electromagnetic form factors (EMFFs) at large momentum transfer has generated a large and increasing amount of experimental and theoretical interest over the last several decades. EMFFs provide precision benchmarks for theoretical modeling of nucleon structure and ab initio predictions in lattice QCD. Additionally, precise knowledge of the form factors at...
In this talk I present our work on the calculation of exclusive single jet and dijet production cross sections in polarized DIS. The NLO accuracy results are obtained with our extension of the dipole subtraction method to account for initial state polarized processes. In the case of single jet production, we also reach NNLO accuracy by applying the projection-to-Born (P2B) subtraction method....
The transversity distribution function of quarks, $h_1^{q}(x)$, encapsulates the transverse spin structure of the proton at leading twist, where $x$ represents the longitudinal momentum fraction carried by the quark $q$. Extracting $h_1^{q}(x)$ poses a formidable challenge due to its chiral-odd nature. Measurements of final-state hadron pairs in transversely polarized proton-proton...
Charged-current quasielastic neutrino scattering is the signal process in neutrino oscillation experiments and requires precise theoretical prediction for the analysis of modern and future experimental data, starting with the nucleon axial-vector form factor. In this talk, I compare a new MINERvA measurement of this form factor with lattice-QCD calculations and deuterium bubble-chamber data,...
During the past several decades a large quantity of high-quality mesonic photo- and electro-production data have been measured at electromagnetic facilities worldwide. By contrast, meson-beam data for these same final states are mostly outdated, largely of poorer quality, or even non-existent, especially those involving spin asymmetries and polarizations. Thus, existing meson beam results...
A deeper understanding of the nucleon structure can be achieved through the study of Generalized Parton Distributions (GPDs).
The particularity of GPDs is that they convey an image of the nucleon structure where the longitudinal momentum and the
transverse spatial position of the partons inside the nucleon are correlated. Moreover, GPDs allow the quantification,
via Ji's sum rule, of the...
Over the last decades, tremendous progress has been made in understanding the 3D partonic structure of strongly-interacting systems like the nucleon in terms of generalized parton distributions (GPDs) and transverse-momentum-dependent parton distributions (TMDs). In this presentation, we briefly describe the status of this field and highlight some recent developments.
Fragmentation functions describe the formation of confined, final state hadrons out of asymptotically-free, high-energetic partons. They therefore help us understand the process of confinement. Additionally, they are also the most important tool to learn about the flavor, spin and transverse momentum of the fragmenting partons and thus access the corresponding parton distribution functions in...
Many interactions with nuclei can be described in terms of convolutions of universal parton distributions. These parton distributions describe the way quarks and gluons conspire to create the hadrons. Over the past decade these distributions have been inferred from matrix elements calculating with Lattice QCD. These matrix elements are similar convolutions of the parton distribution as cross...
AMBER is a new fixed-target experiment at the CERN/SPS for the study of
Hadron Physics, thanks to a versatile beamline capable of providing muon and hadron beams over a wide energy range and a multipurpose modular spectrometer. The emergence of hadron mass phenomenom, central for our undertanding of QCD, can be experimentally addressed from the AMBER measurements of hadron radii,...
The Generalized Parton Distributions (GPDs) paradigm has profoundly renewed the understanding of the nucleon structure. As describing the correlations between partons, GPDs allow us to access static and dynamical information about the nucleon structure, ultimately learning about the mechanics of Quantum Chromodynamics. This comprises the total angular momentum of the nucleon carried by the...
The polarizabilities of a composite system such as the proton are elementary structure constants. They describe its response to an external electromagnetic (EM) field and quantify the deformation of the charge and magnetization distributions inside the proton caused by the electric or magnetic field, respectively. When studied through the virtual Compton scattering process, the virtuality of...
I will present some recent lattice QCD results on parton distribution functions, generalized parton distribution functions and distribution amplitudes. I will focus on results obtained using perturbative matching coefficients computed beyond the next-to-leading order in the strong coupling, specifically using next-to-next-to-leading order matching coefficients as well as incorporating various...
Generalized parton distributions (GPDs) are important quantities that characterize the 3-D structure of hadrons and complement the information extracted from TMDs. They provide information about the partons’ momentum distribution and also on their distribution in position space. The non-perturbative part of the cross-section of high-energy processes may be expanded in terms of the process's...
In its report, the DPAP observed that ``there is significant support in the community and from the panel for a second general-purpose detector system to be installed in IR8 when resources are available.'' Such a detector would unlock the full discovery potential of the EIC by providing cross checks of results from ePIC, and reduce the combined systematic uncertainties. And in combination with...
In this presentation we would like to determine the properties of the lightest resonance in
the baryonic sector of QCD: the Delta(1232) resonance. Using two-hadron operators we calculate the finite volume QCD energy spectrum of $\pi-N$ in the $p$-wave. Using Luescher formalism we can predict the mass and the width of the delta resonance. In our analysis we probe the Luescher formula by...
We investigate contributions of excited states to nucleon matrix elements by studying the two- and three-point functions using nucleon and pion-nucleon interpolating fields. This study is made using twisted mass fermion ensembles with pion masses 346 MeV and 131 MeV. We construct an improved nucleon interpolating field with the generalized eigenvalue problem of two-point functions, and use it...
The STAR experiment at the Relativistic Heavy-Ion Collider has recently released findings regarding exclusive coherent and incoherent photoproduction of $J/\psi$ mesons in Au+Au ultra-peripheral collisions (UPCs). In this talk, I will delve into the preliminary findings and examine how they influence our understanding of nuclear parton density within heavy nuclei and the event-by-event density...
Machine learning and AI are rapidly growing areas of research offering various avenues for exploration in high-energy nuclear physics. Novel tools including generative modeling, regression, and classification are poised to have a significant impact on theoretical and experimental research efforts. In this talk, I will review recent progress in the context of hadron structure, spin physics,...
Different parts of the QCD phase diagram in the plane temperature - baryon density are expected
to be relevant for early stages of the Universe, neutron stars, heavy ion collision experiments.
From theoretical point of view a lot of information about the QCD phase diagram and QCD thermodynamics
can be extracted using lattice ab-initio methods. In this talk I present an overview of
the...
Quantum computing is rapidly emerging as a new method of scientific computing. It has the potential to solve problems much faster than it is possible with classical computers. Examples are applications in logistics, drug design, medicine finances and many more. In addition, with quantum computers problems can be tackled that are very hard or even impossible to address with classical...
The study of baryonic excited states provides fundamental information on the internal structure of the nucleon and on the degrees of freedom that are relevant for QCD at low energies. N* are composite states and are sensitive to details of the how quarks are confined. Meson photo-and electro-production reactions have provided complementary information on light quark baryon spectroscopy for...
We present a data-driven analysis of the S-wave $\pi\pi\to\pi\pi$ and $\pi K \to \pi K$ reactions using the partial-wave dispersion relation. The contributions from the left-hand cuts are accounted for in a model-independent way using the Taylor expansion in a suitably constructed conformal variable. The fits are performed to experimental and lattice data. Our central result is the hadronic...
The US Nuclear Physics community recently completed its Long Range Plan process. The US Nuclear Science Advisory Committee (NSAC), a federal advisory committee appointed jointly by the US Department of Energy, Office of Science, and Directorate for Mathematical and Physical Sciences, the US National Science Foundation, approved the 2023 Long Range Plan "A New Era of Discovery - 2023 Long Range...
We compute the quark and gluon momentum fraction for the pion and kaon. This is done by employing lattice quantum chromodynamics simulations. We use three gauge ensembles of twisted mass fermions generated by the Extended Twisted Mass Collaboration with two degenerate light quarks and non-degenerate strange and charm quarks. All quark masses are tuned to approximately their physical values....
We explore the phase structure of the lattice Schwinger model in the presence of a toplogical $\theta$-term, a regime in which conventional Monte Carlo simulations suffer from the sign problem, using the variational quantum eigensolver (VQE). Constructing a suitable variational ansatz circuit for the lattice model using symmetry-preserving 2-qubit gates, we perform classical simulations...
Axions and axion-like particles (ALPs) are one of the most widely discussed extensions of the Standard Model when it comes to the strong CP problem and dark matter candidates. Current experiments are focused on the indirect searches of invisible pseudoscalars in a wide parameter range. In this paper we investigate limits on ALP mass, and its couplings to photons and leptons from 3-photon...
Chern-Simons gauge theories have a deep and broad impact on a wide range of physics research, ranging from parity anomalies in quantum field theory to the theory of the integer and fractional quantum Hall effects, and the effective field theory description of chiral spin liquids in condensed matter physics. Despite the fact that Chern-Simons theories are well understood as a continuum field...
We evaluate the transverse momentum-dependent parton distribution functions for the pion and kaon by computing the quasi-beam functions with asymmetric staple-shaped quark bilinear operators and combine it with the soft function and Collins-Soper kernels. These are computed within lattice QCD using an $\mathcal{N}_f= 2 + 1 + 1$ twisted mass fermion ensemble of lattice size $24^3 \times 48$,...
Spectroscopy experiments at the precision frontier allow us to study low-energy nuclear structure, test bound-state QED, refine fundamental constants, and potentially find New Physics. As the experimental uncertainties are continuously improved, theory predictions need to follow suit.
The finite-size corrections to the spectra of hydrogen-like atoms are often expanded in terms of the moments...
A well-known challenge when simulating Lattice Gauge theories (LGT) is so-called critical slowing down, which refers to the exponential increase of the autocorrelation time as the lattice spacing is reduced and approaches the continuum limit. Previously, normalizing flows, combined with Lüscher’s trivializing maps, have been proposed as an alternative approach to Hybrid Monte Carlo (HMC),...
We propose a novel direct search experiment for the hypothetical X17 particle. In recent years researchers from the ATOMKI Collaboration have reported anomalous signals around 17 MeV in excited 8Be, 4He and 12C nuclear decays via internal pair creation. On the theory side this has set off a flurry of research, which found that the anomalies could be explained by a new light (~17 MeV)...
