Electromagnetic processes are essential and versatile tools in studying myriad aspects of hadronic and nuclear physics. This talk will offer a tour of the various ways in which electromagnetic processes and probes are used to inform our understanding of hadron structure, hadronization mechanisms, what partonic bound states exist, and properties of extreme nuclear matter. We’ll also consider...
I’ll give my personal perspective on a general overview of the most recent and relevant theoretical developments about how we picture the internal structure of hadrons.
The anomalous magnetic moments of the muon and the electron, 𝑎μ and 𝑎ₑ, are precision benchmarks of the Standard Model and promising New-Physics probes. The hadronic vacuum polarization (HVP) contribution remains the dominant source of uncertainty, a problem compounded by the current tension between data-driven (dispersive) and lattice QCD evaluations. I will discuss the status of the HVP...
The anomalous magnetic moment of the muon, $a_\mu$, remains a benchmark precision test of the Standard Model. The long-standing tension between experiment and theory has driven major progress in recent years, culminating in the latest White Paper, which incorporates state-of-the-art lattice QCD determinations of the hadronic vacuum polarization (HVP). These first-principles results, obtained...
The rapid progress in AI/ML has led to numerous applications in theoretical nuclear physics, often transforming how we carry out calculations and analyze data. I will review recent developments, including generative modeling of collider events, simulation-based inference at the event level, and novel search strategies for physics beyond the Standard Model. These techniques are relevant to...
In this talk, I will show how effective field theory can be combined with dispersion theory to provide a representation of the nucleon's electromagnetic form factors that incorporates the correct analytical structure and the dynamics of QCD at low energy. As an application, I will present how this approach contributes to the determination of the proton's charge and magnetic radii, as well as...
Short-ranged correlations (SRCs) provide insight into the fundamental forces that drive nuclear dynamics. Current experimental goals in this area include increasing precision in two-nucleon (2N) observables and the discovery and characterization of 3N SRCs. Exclusive measurements for these efforts require immense statistics and, given the tensor force’s preference for neutron-proton pairing,...
Nucleon electroweak form factors contain relevant details about hadronic structure and strong interactions in the nonperturbative regime. This information is encoded in their dependence on the momentum transferred to the nucleon by external probes but also in their quark-mass dependence, which is accessible by Lattice QCD (LQCD) simulations.
In our study we rely on relativistic chiral...
Chiral effective field theory has become a standard tool to analyze low-energy reactions involving pions, nucleons and external electroweak sources. I will briefly describe conceptual foundations of this method, review our recent efforts towards developing it into a precision tool for low-energy nuclear physics and discuss some of the remaining challenges.
Obtaining high-precision predictions of nuclear masses, or equivalently nuclear binding energies, $E_b$, remains an important goal in nuclear-physics research. Recently, many AI-based tools have shown promising results on this task, some achieving a precision that surpasses the best human models. However, the utility of these AI models remains in question given that predictions are only useful...
We perform a coupled-channel dispersive analysis of $γ^{(∗)}γ^{(∗)} \to \pi\pi/\pi\eta/K\bar{K}$ using a modified Muskhelishvili–Omnès framework that enforces analyticity and unitarity, modeling the left-hand cut with pion/kaon and vector-meson pole terms. Both unsubtracted and subtracted forms are studied, the latter incorporating Adler-zero constraints. The S-wave $\pi\pi/K\bar{K}_{I = 0}$...
At the new high-intensity, low-energy electron accelerator MESA, the MAGIX experiment will enable high-precision scattering studies focused on the structure of hadrons and few-body systems, dark sector searches, as well as investigations of reactions relevant to nuclear astrophysics.
MAGIX features a fully windowless scattering chamber housing an internal gas jet target that can be operated...
We analyze the processes $e^+ e^- \to \gamma^* \to J/\psi \, \pi \, \pi \, (K \bar{K})$ and $e^+ e^- \to \gamma^* \to h_c \, \pi \, \pi$ using the recently proposed Dalitz-plot decomposition approach, based on the helicity formalism for three-body decays. Within a Lagrangian-based toy model, we validate key aspects of this approach, namely the factorization of the overall rotation for all...
Various extensions of the Standard Model give rise to BSM particles with masses in the MeV to sub-GeV range. Such particles are often associated with dark matter, the strong CP problem and the $\left(g-2\right)_{\mu}$ anomaly. In this work, we examine the experimental constraints on such particles that can be derived from near-future high-precision experiments, including the MESA facility and...
At the Institute for Nuclear Physics in Mainz, the new electron accelerator MESA will be operational shortly. The high-power beam dump of the P2 experiment (150 MeV, 150 $\mu$A) is ideally suited for a parasitic dark sector experiment – DarkMESA.
The experiment is designed for the detection of Light Dark Matter (LDM), which in the simplest model couples to a massive vector particle, the...
We present our preliminary determination of the charge radii of light mesons using the PACS10 configurations, which were generated at the physical point on large volumes of more than $(10\,\text{fm})^3$ by the PACS Collaboration. In general, charge radius calculations suffer from systematic effects due to chiral extrapolation, finite lattice spacing effect, finite volume effect, and the choice...
In recent years, a number of charmonium-like XYZ states have been observed above the open-charm threshold in experiments like BABAR, BESIII, Belle(II) and LHCb. Their properties often go against our expectations for regular charmonium states, rendering their interpretation difficult. In this talk, I will give an overview of recent activities aiming to shed light on the nature of the XYZ states.
I will review recent advances in studying three-particle interactions directly from lattice QCD. By employing mathematical relations that connect discrete finite-volume energies and matrix elements to physical scattering and decay amplitudes, it is now possible to calculate observables that go beyond the single-hadron or elastic two-hadron regime. In addition to outlining the formalism, I will...
The detailed understanding of how quantum chromodynamics (QCD) gives rise to the spectrum of hadrons is currently one of the biggest open questions in hadron physics. Most of the observed states are classified as quark-antiquark mesons or three-quark baryons. However, QCD allows for a much richer spectrum with more complex configurations. Experimental evidence exists for such non-conventional...
The PRad-II and X17 Experiments are planned to run in Jefferson Lab’s Hall B in 2026. The common experimental setup includes a large-volume vacuum system, two planes of GEM tracking detectors for improved vertex and angle reconstruction, and a high-resolution calorimeter (HyCal). These experiments strive to give definite answers to long-standing questions in hadron physics. The X17 experiment...
Understanding the interactions among strange hadrons is crucial for developing a realistic equation of state of nuclear matter in dense environments as in the interior of neutron stars. In recent years, significant theoretical progress has been achieved through Effective Field Theories, which provide interaction models anchored to experimental data, and through Lattice QCD calculations that...
The Electron Ion Collider (EIC) is designed to further our understanding of hadronic physics. However, it could also provide opportunities to look for new phenomena beyond the Standard Model. In this talk, we will provide examples of such physics, with a focus on new light particles that may be associated with a dark sector. We will illustrate how the EIC can probe new model parameter space...
Testing the foundations of quantum mechanics requires experiments with
extremely high sensitivity to the detection of events, which, if they
occur, would have an extremely low rate. The VIP collaboration at the Gran
Sasso National Laboratory (LNGS) is performing tests on the spontaneous
collapse of the wave function, where recent results indicate that
different collapse models...
A key step toward a better understanding of the nucleon structure is the study of Generalized Parton Distributions (GPDs). GPDs are nowadays the object of an intense effort of research since 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 give access, via Ji's sum...
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...
Generalized Parton Distributions (GPDs) provide a unified framework for exploring the three-dimensional structure of hadrons, encoding correlations between spatial and momentum distributions as well as spin and orbital angular momenta of quarks and gluons. Lattice QCD offers a first-principles approach to access these nonperturbative quantities, but long-standing challenges have limited...
The electromagnetic polarizabilities of the proton are fundamental structure constants, that describe the proton’s 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...
The structure of hadrons relevant for deep-inelastic scattering are completely characterised by the Compton amplitude. It is possible to directly calculate the Compton amplitude by taking advantage of the familiar Feynman-Hellmann approach applied in the context of lattice QCD. In principle, the x-dependent structure functions can be recovered from the amplitude or the amplitude itself can be...
Theoretical control of soft interactions is fundamental to establish TMD factorization. It is possible to sistematically include soft interactions through soft modes in bacckground field method to reach a consistente factorization of SIDIS or Drell-Yan cross sections at next-to-leading power, where all nonperturbative terms are expressed as martix elements of field operators. As a practical...
Nuclear multipole resonances have long been studied as a source of information on bulk nuclear properties. The nuclear dipole response has received much experimental and theoretical attention due to the proposed correlation between the pygmy dipole resonance (PDR) and the nuclear equation of state. Such a connection interprets the PDR in neutron-rich nuclei as the oscillation of the neutron...
We present a one-loop perturbative study of unpolarized twist-two generalized parton distributions (GPDs) for external on-shell gluon states. A finite quark mass 𝑚 is kept throughout: it serves as an infrared regulator and, crucially, enables an explicit realization of the full trace-anomaly relation. By taking second Mellin moments, we extract the associated gravitational form factors (GFFs)...
Gluons play a central role in the proton’s structure, carrying a substantial fraction of its momentum and driving its dynamics at small Bjorken-$x$. A precise determination of the unpolarized gluon parton distribution function (PDF) from first principles is essential for understanding QCD and for reducing uncertainties in high-energy collider predictions. In this talk, we extend our work on...
Motivated by the expected improvement in the experimental determination of the $\mu$H Lamb shift measurement, I will present an updated fit of the unpolarised nucleon structure functions from available data in the nucleon resonance region in combination with Regge fits to the high-energy and deep inelastic region. The evaluation of the structure functions in the resonance region is building...
I will discuss a lattice QCD calculation of the nucleon electric polarizabilities at the physical pion mass. Our findings reveal the substantial contributions of the Nπ states to these polarizabilities. Without considering these contributions, the lattice results fall significantly below the experimental values, consistent with previous lattice studies. This observation has motivated us to...
An overview of the experimental activities for the study of generalised parton distributions will be presented. These include existing measurements of exclusive processes in lepton-hadron and hadron-hadron interactions as well as planned activities for the future.
Generalized parton distributions (GPDs) offer a powerful framework to access the multidimensional structure of hadrons, allowing in particular for so-called nucleon tomography and providing access to elements of the hadron energy–momentum tensor. The extraction of GPDs from experimental data is, however, challenging and often cannot be performed in a complete way due to difficulties arising...
The never ending story of baryon time-like form factors continues and renew itself, fed by the powerful process of synergic and mutually reinforcing actions of experiments and theory.
Hyperons, with their self analyzing weak decays give the unique possibility to investigate the complex nature of form factors and mainly to test concepts based on first principles, which can be exploited to...
In this talk I will review the current status of transverse momentum dependent (TMD) physics and related phenomena, including both unpolarized and polarized observables. Such studies give us insight into the 3-dimensional structure of hadrons. The focus of the talk will be on recent developments in theory and phenomenology regarding the extraction of TMD parton distribution functions and...
In recent years, significant progress has been made in extracting transverse-momentum-dependent (TMD) hadron structure from lattice QCD. In this talk, I will give a brief overview of recent developments in lattice calculations of TMD physics, including the determination of the soft function, the Collins–Soper kernel, and the computation of TMD parton distribution functions and TMD wave functions.
Lattice QCD calculations have now reached the maturity required to determine the properties of hadronic resonances from first principles. In this talk, I will review recent progress on baryon resonances, with particular emphasis on the $\Lambda(1405)$, the $\Delta(1232)$, and two-nucleon systems. I will also outline the path toward exploring higher-lying resonances in QCD, highlighting recent...
In this talk, we discuss the recent progress in lattice QCD determinations of generalized parton distributions. The recently developed framework of asymmetric frames of reference, now complete for the vector, axial vector and tensor cases, allows for cost effective calculations of GPDs across a broad range of kinematics. This makes the prospects of their full mapping realistic in the near...
Proton and neutron electric and magnetic form factors are the primary characteristics of their spatial structure and have been studied extensively over the past half-century. At large values of the momentum transfer $Q^2$ they should reveal transition from nonperturbative to perturbative QCD dynamics and effects of quark orbital angular momenta and diquark correlations. Currently, these form...
We present our results for the kaon semileptonic form factors calculated
by using the $N_f=2+1$ and $2+1+1$ PACS10 configuration, whose physical volumes
are more than $($10 fm$)^4$ at the physical quark masses in the lattice spacings
from 0.04 to 0.08 fm. The configurations were generated using the Iwasaki
gauge action and stout-smeared clover quark action. The form factors near
zero...
The existence of two-nucleon short-range correlations (2N SRCs) has been well established by a series of experiments at SLAC and Jefferson Lab. The inclusive measurements showed a universal behavior in A/D cross section ratios of quasielastic scattering at x>1 and moderate Q2 yielding a constant value. In these kinematics mean field contributions fall off rapidly and 2N SRC contributions...
The low-energy limit of QCD is represented by a tower of effective field theories (EFTs): Chiral, Pionless, Halo/Cluster, and Roto-Vibrational, with perhaps others still to be developed. EFTs have transformed the landscape of nuclear theory by providing a systematic framework to account for multi-body forces and currents following the same tenets used in other areas of physics. However, issues...
Lattice QCD has matured into a powerful nonperturbative tool for directly probing the low-energy regime of the strong interaction from the QCD Lagrangian. Specifically, lattice QCD now offers quantitative insights into two- and three-nucleon interactions, nuclear binding energies, hypernuclear forces, and electroweak matrix elements relevant to neutrino-nucleus scattering and double beta...
AMBER is a new QCD facility at CERN's SPS M2 secondary beam line, which aims to study fundamental properties of hadrons. The first approved experimental phase includes measuring the antiproton production cross-section, which is essential for indirect dark matter searches using cosmic-ray antiprotons. It also includes measuring the proton's charge radius using high-energy muons and...
The intensity frontier offers a complementary approach to high-energy colliders, as high-precision measurements can provide unprecedented constraints on new physics, fundamental interactions, and the structure of matter. The Mainz Energy-recovering Superconducting Accelerator (MESA) is a cutting-edge facility that will push the limits of high-intensity, low-energy hadronic physics. MESA’s...
I review recent developments in the field of heavy ion collisions and quark gluon plasma physics with focus on the role of nucleon and nuclear structure, electromagnetic probes, as well as connections to the future Electron Ion Collider.
The status and plans for experimental programs in hadronic physics in Asia, Europe and N. America will be summarized.
The MAinz Gas Injection Target EXperiment (MAGIX) will be operated at the Mainz Energy-Recovering Superconducting Accelerator (MESA), performing high-precision electron scattering experiments on a variety of targets, ranging from hydrogen to argon.
The setup includes a windowless gas jet target, followed by two high-resolution magnetic spectrometers that focus the scattered electrons onto...
We present a practical approach for implementing the overlap Dirac operator in lattice QCD that combines the Kenney-Laub (KL) rational iterates for approximating the matrix sign function, their partial fraction decomposition enabling Multi-Shift Conjugate Gradient solvers, and the parameter-free Brillouin operator as kernel. This method requires no spectral information, avoiding the costly...
AMBER is a new QCD facility at CERN's SPS M2 secondary beam line, which aims to study fundamental properties of hadrons. The first approved experimental phase includes measuring the antiproton production cross-section, which is essential for indirect dark matter searches using cosmic-ray antiprotons. It also includes measuring the proton's charge radius using high-energy muons and...
In this presentation I will show how we can constrain Dark Matter (DM) scenarios with the supernova remnant HESS J1731-347. We assume the compact object to be an admixture of DM and Neutron Star, and presume the former to behave as a free Fermi gas. For the Neutron Star we use recently calculated regulator-independent equations of state for neutron stars obtained from first principles. Using...
We perform a global analysis of negative-strangeness meson–baryon scattering using lattice QCD and experimental data within the Chiral Unitary Approach. The lattice data are analyzed via the Lüscher formalism, including coupled channels. Systematic uncertainties from data limitations, ambiguities, and framework dependence are quantified using statistical tools. We present pole positions for...
Medical Physics has grown out of nuclear physics from the very beginning and today the nuclear physics detectors, data acquisition systems, simulations, and particle accelerator systems that make up the backbone of medical imaging and cancer treatment systems in the clinic have integrated artificial intelligence and machine learning (AI/ML) deeply into their research and development cycles and...
Quantum computing uses principles from quantum mechanics that might solve certain problems that classical computers find very hard or slow to handle. It can be especially helpful in areas like optimization, cryptography and simulating quantum systems. A key aspect of this is quantum coherence, we discuss the role of resource theory in understanding the potential power of quantum computing....
The P2 experiment at the future MESA accelerator in Mainz plans to measure the weak mixing angle $\sin^2(\theta_W)$ in parity violating elastic electron-proton scattering. The aim of the experiment is a very precise measurement of the weak mixing angle with an accuracy of $0.14\%$ at a low four-momentum transfer of $Q^2=4.5\cdot 10^{-3} \ \mathrm{GeV^2}$. In order to achieve this accuracy, it...
The P2 experiment aims to precisely measure the weak mixing angle $\sin^2\theta_W$ through parity-violating electron-proton scattering at low momentum transfer. This is projected to achieve a relative precision of $0.14\%$ for $\sin^2\theta_W$. A crucial component of the experiment is a $60 \, \text{cm}$ long liquid hydrogen ($\text{lH}_2$) target. It is designed to handle a heat load of $4000...
In the ongoing search for light dark matter, the DarkMESA and NuDoubt$^{++}$ experiments have combined their efforts to probe a new region of parameter space. DarkMESA is a forthcoming electron beam dump experiment to be located in the new MESA accelerator facility in Mainz, designed to detect light dark matter particles mediated by a hypothetical dark photon $\gamma’$ with the use of a...
We present the first proof of concept extraction using neural networks (NNs) of the unpolarized transverse-momentum distributions (TMDs) at next-to-next-to-next-to-leading logarithmic (N$^3$LL) accuracy. By offering a more flexible and adaptable approach, NNs overcome some of the limitations of traditional functional forms, providing a better description of data.
Moreover, we present the...
Inclusive processes pose a long-standing challenge for lattice QCD due to their inherently multi-hadron nature and the need to access fully summed final states. Here, we demonstrate how first-principles methods can now overcome these obstacles through spectral reconstruction techniques. We present a first-principles lattice QCD study of the inclusive semileptonic decays of the $D_s$ meson,...
We present a first-principles determination of the unpolarized GPDs of the pion and kaon from lattice QCD using a Twisted Mass N_f = 2+1+1 ensemble reproducing a pion mass of 260 MeV, and a kaon mass of 540 MeV. Using boosted meson states and gauge-invariant nonlocal quark bilinears, we compute off-forward matrix elements over a range of meson momenta, momentum transfers t, focusing on zero...
I review recent developments in the field of heavy ion collisions and quark gluon plasma physics with focus on the role of nucleon and nuclear structure, electromagnetic probes, as well as connections to the future Electron Ion Collider.
The never ending story of baryon time-like form factors continues and renew itself, fed by the powerful process of synergic and mutually reinforcing actions of experiments and theory.
Hyperons, with their self analyzing weak decays give the unique possibility to investigate the complex nature of form factors and mainly to test concepts based on first principles, which can be exploited to...
Reconstructing the internal quark and gluon structure of nucleons and nuclei is a central goal of the JLab 12 GeV program and the future Electron–Ion Collider. Achieving this goal is a formidable challenge that demands the integration of theory, experiment, and data science. In this talk, I will present recent progress by the JAM Collaboration toward this mission and highlight emerging...
The fusion barrier studies at energies around the Coulomb barrier have been a topic of great interest. At these energies, the coupling between relative motion and internal degrees of freedom of colliding heavy ions is strongly affected, which results in a number of distributed barriers instead of a single barrier (Bfus) [1-6]. A barrier distribution (BD) can be extracted experimentally from...
The P2 experiment aims for a high precision measurement of the weak mixing angle, a fundamental parameter of the Standard Model. The weak mixing angle will be extracted from the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer, with an expected raw asymmetry of $A_\text{raw} = 0.2403\times 10^{-7}$. The central component of the detector system is an...
We assess the potential of using deuteron photodisintegration around the neutron quasi-free peak as a dual-purpose experiment to simultaneously constrain neutron polarizabilities and probe physics beyond the Standard Model. Such a combined approach would uniquely tackle two distinct research programs simultaneously: nucleon electromagnetic structure and searches for light new physics.
The...
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...
We present a lattice QCD study of $DD_s$ scattering in the $J^P = 0^+$ channel employing a newly proposed finite-volume Hamiltonian method using the Lippmann-Schwinger equation formulated in the plane-wave basis. This novel approach provides a direct way to analyze two-hadron interacting systems without relying on the traditional Lüscher formalism formulated in the partial-wave basis. From the...
Precision calculations from lattice Quantum Chromodynamics (QCD) play a crucial role in connecting the theory of strong interactions to experimental measurements. A central challenge is controlling statistical uncertainties in correlation functions. We explore the use of Low Mode Averaging (LMA), a noise reduction technique that exploits the low-lying eigenmodes of the Dirac operator to...
The intensity frontier offers a complementary approach to high-energy colliders, as high-precision measurements can provide unprecedented constraints on new physics, fundamental interactions, and the structure of matter. The Mainz Energy-recovering Superconducting Accelerator (MESA) is a cutting-edge facility that will push the limits of high-intensity, low-energy hadronic physics. MESA’s...
The neural network framework allows us to obtain empirical fits to electron scattering cross sections on carbon over a wide kinematic region. Transfer learning makes it possible to adapt a deep neural network trained on one type of data to new problems. We apply transfer learning to derive a new model from a previously obtained set of neural networks trained on electron-carbon cross-section...
We determine the nucleon axial, scalar and tensor charges at the continuum limit by analyzing three $N_f=2+1+1$
twisted mass fermion ensembles with all quark masses tuned to approximately their physical values. We include all contributions from valence and sea quarks. We use the Akaike Information Criterion to evaluate systematic errors due to excited states and the continuum...
An overview of the experimental activities for the study of generalised parton distributions will be presented. These include existing measurements of exclusive processes in lepton-hadron and hadron-hadron interactions as well as planned activities for the future.
Modern nuclear physics experiments produce data of unprecedented scale and complexity, making Artificial Intelligence (AI) and Machine Learning (ML) essential tools for effective experimental optimization and data analysis. AI and ML techniques now impact every stage of the experimental workflow—from detector calibration and real-time data reduction to event reconstruction and physics...
We calculate the Next to Leading Order (NLO) corrections to single inclusive hadron production in DIS (SIDIS) in the forward rapidity region using the Color Glass Condensate (CGC) formalism. We then consider the kinematic region where the transverse momentum of the produced hadron is much less than the virtuality of the photon and show that there are large (Sudakov) logs originating from this...
The Electron-Ion Collider will explore the internal structure of nucleons and nuclei with unprecedented precision. By colliding polarized electrons with polarized protons and a range of nuclei across a broad kinematic regime, the EIC will enable multi-dimensional probes of nucleon structure, including TMDs, GPDs, and other partonic correlations. These measurements are essential for...
Recent studies of spin and azimuthal asymmetries at JLab suggest that separation of different dynamical contributions may be critical for interpretation of observables in both exclusive and semi-inclusive production of hadrons in electroproduction. Measurements of multiparticle final states in multidimensional space will be needed to sort out all disagreements with theory predictions and...
We present the first lattice QCD determination of the Λ → N vector and axial-vector form factors, which are essential inputs for studying the semileptonic decay Λ → pℓν¯ℓ. This channel provides a clean, heoretically controlled avenue for extracting the CKM matrix element |Vus| from the baryon sector. Our analysis uses a gauge ensemble with physical light, strange, and charm quark masses and...
Two-photon exchange (TPE) is one of the leading explanations for discrepancies in measurements of the proton electromagnetic form factors. It has been proposed that TPE could impact not only elastic scattering but also the cross sections for both inclusive deep inelastic scattering (DIS) and semi-inclusive DIS, thereby affecting the interpretation of DIS structure functions in terms of parton...
In this work, we propose the formalism of subtracted dispersion relations for virtual Compton scattering (VCS) off a proton target as a tool for extracting generalized polarizabilities (GPs) of the proton. This approach offers advantages over the one based on unsubtracted dispersion relations used so far in interpreting the data, particularly in reducing the model dependence.
In this...
The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab has been delivering the world’s highest intensity and highest precision multi-GeV electron beams for more than 25 years. The Nuclear Physics community has resourcefully exploited these advanced accelerator facility for studies of the fundamental interactions and this research has impacted the entirety of Nuclear...
The MAinz Gas Injection Target EXperiment (MAGIX) experiment at the
Mainz Energy-Recovering Superconducting Accelerator (MESA) requires precise event selection and background supression. This poster presents the dedicated Trigger Veto System developed for that purpose.
The MAGIX setup consists of a windowless gas jet target, followed by two high-resolution magnetic spectrometers that focus...
We present a calculation of the second, third and fourth Mellin moments of the pion and the kaon in lattice QCD. We use one ensemble of gauge configurations with two degenerate light, the strange and charm quarks with masses tuned to their physical ones. The renormalization is carried out non-perturbatively using RI-MOM and the values at given at a scale of 2 GeV in the $\bar{MS}$ scheme. We...
The Mellin moments can be used to construct parton distribution functions that are essential for phenomenology. Since they are non-perturbative quantities, they are challenging to compute. Lattice QCD provides the frame to compute generalized form factors (GFFs) providing these moments and unveil the polynomiality structure of generalized parton distributions. In this work, we present the...
The size of the proton has traditionally been defined by its charge radius, neglecting the role of gluons despite their dominance in its structure. Here we report the first global experimental extraction of the proton’s total scalar energy density, reconstructed from near-threshold $J/\psi$ production data to provide the gluonic contribution and the quark contribution from DVCS. We show that...
The search for “missing resonances,” first highlighted by Koniuk and Isgur in 1980, has shaped the field of baryon spectroscopy for more than four decades. It inspired worldwide experimental programs and new theoretical approaches to uncover the spectrum and structure of excited nucleon states.
This talk will review recent progress from meson photo- and electroproduction studies that have...
We present a lattice QCD analysis of unpolarised generalised parton distri-
butions (GPDs) of the proton. Our calculations are done on an ensamble with
Nf = 2 + 1 + 1 (degenerate light quarks, strange and charm quarks) twisted
mass fermions at physical mass with a clover improvement and lattice spacing
a = 0.08 fm. We use Large Momentum Effective Theory (LaMET) to anlayse
and match the...
