Hadron Imaging with GPDs: High-Precision Global Analysis and Lattice QCD

Jun 14, 2026, 8:00 PM → Jun 19, 2026, 2:00 PM Europe/Rome

Aula Renzo Leonardi (ECT*)

David Richards, Ian Cloet, Martha Constantinou, Raphaël Dupré, Vladimir Braun

WARNING: for hotel bookings do not give your data to any external services upon email request; there are known cases of fraud

Recent years have seen major advances in our understanding of the quark and gluon content of hadrons. Yet, achieving a fully quantitative three-dimensional picture of parton distributions within nucleons remains a critical challenge in QCD. We propose a workshop titled “Toward Next-Generation QCD for Hadron Imaging: High-Precision Global Analysis and Lattice QCD" with the goal of fostering a focused, synergistic effort toward the high-precision extraction of GPDs. This workshop will bring together experts in global QCD analysis, lattice QCD, and advanced data analysis techniques to develop a common framework for GPD reconstruction. We also plan to include experts in TMD studies to explore methodological overlap and complementarity. Key goals include refining theoretical formulations, integrating lattice constraints into global fits, and advancing strategies to solve the underlying inverse problems using modern tools. In contrast to previous ECT* workshops, which emphasized interpretative aspects of hadron structure, this workshop will focus on theoretical and numerical strategies for precision extraction. By doing so, it aims to create a new momentum for quantitative hadron tomography. The workshop will also promote interdisciplinary collaboration by bringing together students, postdoctoral fellows, and senior scientists, fostering the exchange of innovative ideas across all career stages.

Sun, June 14

8:00 PM → 10:00 PM Welcome Dinner

Green Tower restaurant
Address: via Torre Verde 29 in Trento

Mon, June 15

9:00 AM → 9:20 AM Registration

9:20 AM → 9:40 AM Welcome

9:20 AM ECT* Director, Bira van Kolck

Speaker: Ubirajara van Kolck (ECT*, Trento)

9:35 AM Workshop Organizers

Speaker: Martha Constantinou

9:40 AM → 10:40 AM Session 1: Martha Constantinou (Chair)

9:40 AM Experimental measurements probing GPDs: status and prospects

An update of the existing experimental measurements sensitive to GPDs will be presented and the plans for future measurements accessing GPDs will be discussed. Here, the complementarity between different physics channels and collision systems will be highlighted.

Speaker: Charlotte Van Hulse (VUB)

GPDLattice26_CVH.pdf

10:10 AM Nucleon structure through GPD studies: recent results from CLAS12

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 position of the partons inside the nucleon are correlated. Moreover, GPDs give access, via Ji's sum rule, to the contribution of the orbital angular momentum of the quarks to the nucleon spin. Deeply Virtual Compton scattering (DVCS), the electroproduction of a real photon off the nucleon at the quark level, is the golden process directly interpretable in terms of GPDs of the nucleon. The GPDs are accessed in DVCS mainly through the measurements of spin-dependent asymmetries. Combining measurements of asymmetries from DVCS experiments on both the neutron and the proton will allow performing the flavor separation of relevant quark GPDs via linear combinations of proton and neutron GPDs.
This talk will be dedicated to the presentation of recent results, from the CLAS12 experiment at Jefferson Lab with the upgraded ~11 GeV CEBAF polarized electron beam, regarding measurements aiming to constrain GPDs. A focus will be on the Beam-Spin Asymmetry (BSA) observable measured from DVCS off the proton with a hydrogen target and a deuterium target. The BSA measurements with free-proton feature a never before examined region of the phase space reaching low values of invariant four-momentum transfer t. Those from bound proton in deuterium will give a hint on medium effects on GPDs. A perspective on GPD-aimed measurements beyond the kinematic constraints from DVCS and its time-reversal counter process, time-like Compton scattering will be shown.

Speaker: Mostafa Hoballah (IJCLab CNRS-IN2P3)

Presentation_HOBALLAH.pdf

10:40 AM → 11:15 AM Coffee break

11:15 AM → 12:45 PM Session 2: Martha Constantinou (Chair)

11:15 AM Conformal moments of the two-loop coefficient functions in DVCS

We develop a new technique and calculate conformal (Gegenbauer) moments of the two-loop coefficient functions in Deeply Virtual Compton Scattering (DVCS). This formulation is necessary for the extraction of the generalized parton distributions from the experimental data to the NNLO accuracy within the Mellin-Barnes approach.

Speaker: Vladimir Braun (Regensburg University)

ECT-Jun-2026.pdf

11:45 AM AI-Assisted Inference and Imaging for Precision Hadron Structure Studies

Precision studies of hadron structure increasingly require the integration of heterogeneous information from experiments, theoretical calculations, and numerical simulations. This talk will present recent developments in AI-assisted inference frameworks for hadron structure studies, including applications of machine learning, simulation-based inference, and generative modeling to global QCD analyses and hadron imaging. Particular emphasis will be placed on methodologies that enable the extraction of multidimensional structure information while maintaining rigorous uncertainty quantification. Connections to lattice QCD, generalized parton distributions, and future Electron-Ion Collider measurements will be discussed, together with prospects for agentic and AI-enabled scientific workflows in nuclear physics.

Speaker: Nobuo Sato (Jefferson Lab)

sato

12:15 PM Partonic Structure of Baryons and Transition GPDs

In this talk, I will discuss the deeply-virtual Compton scattering process involving the transition between a nucleon and a nucleon resonance in the pion-nucleon system, within the framework of GPDs. For the four lowest-lying nucleon resonances, Delta(1232), N(1440), N(1520), and N(1535),
the DVCS amplitude in the Bjorken limit has been expressed in terms of corresponding nucleon-to-resonance GPDs.
Building upon the knowledge of the well studied electromagnetic nucleon-to-resonance transition form factors, which map the quark charge densities in transverse position space, the corresponding GPDs open the prospect to also access the longitudinal momentum distributions of quarks in the transition.
I will discuss the experimental prospects both with CLAS12@JLab and at the EIC.

Speaker: Marc Vanderhaeghen (University Mainz)

vanderhaeghen_ECT*_June2026_v2.pdf

12:45 PM → 2:15 PM Lunch break

2:15 PM → 3:15 PM Session 3: Nobuo Sato (Chair)

2:15 PM Global analysis of GPDs with moment space method

Understanding the mass, spin, and mechanical structure of the nucleon is a central goal of nuclear physics and a key motivation for Jefferson Lab, the future EIC at BNL. In this talk, I will present recent progress in extracting generalized parton distributions and gravitational form factors from exclusive processes, with a focus on a state-of-the-art global analysis combining experimental and lattice-QCD constraints.

Speaker: Yuxun Guo (Lawrence Berkeley National Laboratory/Brookhaven National Lab)

2:45 PM Monte Carlo Extraction of GPDs from global DVCS data

I will present results of a Bayesian Monte Carlo extraction of Generalized Parton Distributions from available Deeply Virtual Compton Scattering data.

Speaker: Eric Moffat (Argonne National Lab)

Moffat_ECF_6_15_26.pdf

3:15 PM → 3:45 PM Coffee Break

3:45 PM → 4:30 PM Session 4: Nobuo Sato (Chair)

Tue, June 16

9:30 AM → 10:30 AM Session 1: David Richards (Chair)

9:30 AM Finite-$t$ and target mass corrections for the short-distance expansion of quasi(pseudo) GPDs

We calculate the ``kinematic'' corrections $t/P_z^2$ and $m_N^2/P_z^2$ to the short distance
expansion of gauge-invariant nonlocal quark-antiquark operators sandwiched
between nucleon states with different momenta. Here $t$ is the momentum
transfer, $m_N$ is the nucleon mass and $P_z$ is the momentum component
in the direction of the quark-antiquark separation, which is assumed to be large.
These matrix elements can be calculated in lattice QCD and, at leading twist,
expressed in terms of moments of the generalized parton distrubutions (GPDs).
Our results allow one to control one of principal uncertainties in such calculations and extend
their region of applicability to larger momentum transfers,
which is important in the quest to access the three-dimension image of the proton.
The calculated corrections turn out to be significant for a realistic lattice QCD setup.

Speaker: Huayu Jiang (Henan Normal University)

kinematic_HYJ.pdf

10:00 AM Recent progress in x-dependent GPDs from lattice QCD

In this talk, we discuss the recent progress in lattice QCD determinations of generalized parton distributions. In particular, we present a unified neural-network-based framework to combine large momentum effective theory (LaMET, quasi-distributions) and short-distance expansion (SDE, pseudo-distributions) in a single analysis, with robust model-independent reconstruction of the x and the t dependence. Additionally, we show our results for GPDs at nonzero skewness with LaMET alone, illustrating the need to aid this extraction by SDF to reconstruct the ERBL region. We discuss the prospects of GPDs from the lattice and argue that they are very favorable, although careful quantification of all systematic effects will be a laborious task. Importantly, future prospects also involve synergies with phenomenology and experiment.

Speaker: Krzysztof Cichy (Adam Mickiewicz University)

cichy-Trento2026.pdf

10:30 AM → 11:15 AM Coffee Break

11:15 AM → 12:45 PM Session 2: David Richards (Chair)

11:15 AM The nucleon unpolarized generalized form factors and Mellin moments up to fourth order

Nucleon Mellin moments of parton distribution functions and generalized parton distributions are computed up to the fourth order in lattice QCD. The computation is performed using one ensemble of twisted mass fermions at the physical pion mass point. We employ boosted frames to access the higher-order Mellin moments of generalized parton distributions. We also extract the generalized formfactors up to fourth order. These results establish benchmarks for future lattice studies and expand the understanding of the partonic structure of the proton.

Speaker: Christian Kummer (University of Cyprus)

ECT_star.pdf

11:45 AM Generalized parton distributions and gravitational form factors at large momentum transfer

Within the soft collinear effective theory (SCET), we derive a factorization theorem which resums Sudakov logarithms $(\alpha_s\ln^2(-t))^n$ to all orders in the quark-in-quark generalized parton distribution (GPD) at large momentum transfer $t$, and perform a consistency check to one-loop. We show that the same Sudakov factor appears in the Feynman contribution to the GPDs of the nucleon. Our result enables the resummation of all the large logarithms $\ln Q^2$ and $\ln^2t$ in exclusive processes with two hard scales $\Lambda_{\rm QCD}^2\ll |t| \ll Q^2$. We also present a SCET power counting analysis of the Feynman contributions to the GPDs and show that the $x$-dependence of GPDs factorizes at large-$t$ with controlled corrections. This in particular implies that any ratio of GPD moments such as the electromagnetic and gravitational form factors (GFF) is perturbatively calculable in this approximation.
Furthermore, we identify a novel order $\alpha_s$ power-law $t$-dependence in the GPD and the $D$-type GFF that will dominate over the standard order $(\alpha_s^2)$ leading twist asymptotic contribution in the phenomenologically relevant region of $t$.

Speaker: Jakob Schoenleber (Technical University Munich)

GPD_factorization_at_large_t__ECT__2026.pdf

12:15 PM Near-threshold Jpsi photoproduction and Gluonic Gravitational Form Factors

I will talk about the near threshold photoproduction of Jpsi and its constrain on the gluonic gravitational form factors.

Speaker: Feng Yuan (Lawrence Berkeley National Laboratory)

GFF_Yuan.pdf

12:45 PM → 2:15 PM Lunch break

2:15 PM → 3:15 PM Session 3: Krzysztof Cichy (Chair)

2:15 PM What Does Lattice Ioffe-Time Data Really Know About the MSbar PDF?

Extracting continuum MSbar PDFs from lattice pseudo-distribution or Ioffe-time matrix elements is a multi-layer inverse problem. The measured matrix elements depend not only on the desired leading-twist distribution, but also on perturbative matching and evolution, finite lattice spacing effects, excited-state contamination, and higher-twist contributions whose separation from leading twist is meaningful only over a restricted range of Wilson-line separations. I will discuss a Bayesian resolution framework for this problem. The leading-twist pseudo-distribution matching and evolution kernels define a forward map from the continuum PDF to lattice observables, while lattice artifacts,
source-sink effects, and higher-twist terms are treated as structured nuisance sectors. By analyzing the whitened singular spectrum and posterior resolution kernels of the full forward problem, one can determine which modes of the MS PDF are identifiable and which are prior- or model-dominated. This approach also provides a quantitative way to study the tradeoff between including larger-z^2 data, which improve nominal x-resolution, and higher-twist contamination, which can invalidate leading-twist extraction.

Speaker: Kostas Orginos (William & Mary)

GPD_beamer.pdf

2:45 PM Pion and Kaon Mellin Moments from Lattice QCD

In recent years, the $x$-dependence of parton distribution functions (PDFs) has become accessible through non-local operators of a boosted hadron by utilizing techniques such as large momentum effective theory (LaMET) and short distance factorization (SDF). Embedded in these distribution functions are Mellin moments, which contain information on fundamental properties of hadrons, such as the fraction of the hadron momentum carried by quarks. Moments can be extracted by utilizing SDF, which can then be benchmark of the validity of PDF construction. The pion is particularly interesting to study as it is the lightest hadron, and its SU(3) symmetry counterpart, the kaon, is also of interest. In studying both of these hadrons, we can compare the up and strange quark contributions individually and study SU(3) symmetry breaking. In this work, we study the extraction of the moments at NLO and NNLO accuracy, as well as study DGLAP evolution to study systematics.

Speaker: Joshua Miller (Temple University)

ECT__2026_Miller.pdf

3:15 PM → 3:45 PM Coffee Break

3:45 PM → 4:15 PM Session 4: Krzysztof Cichy (Chair)

3:45 PM Evidence for Quark Confinement in the Proton

The strong interaction is the fundamental force that holds quarks and the gluon force carriers together to form protons and neutrons and also holds the atomic nucleus together. The theory governing quark-gluon interactions is Quantum Chromodynamics (QCD). A wide variety of experimental data teaches us that quarks and gluons cannot be observed in isolation, a phenomenon known as confinement that is unique to QCD. But no one has used QCD to prove confinement. Here we show how to define and measure the force on quarks in the proton using available experimental data. Direct evidence for confinement is obtained because the force is found to be attractive and constant for a wide range of quark positions. This work guides future experimental efforts aimed at obtaining a rigorous quantitative understanding of confinement.

Speaker: Gerald Miller (UW)

Confinement_Talk.pdf

Wed, June 17

9:30 AM → 10:30 AM Session 1: Feng Yuan (Chair)

9:30 AM Isovector moments of parton distribution functions from the lattice.

We present results for the first and second moments of the
isovector unpolarised, polarised and transversity parton distribution
functions~(PDFs) of the nucleon, sigma and cascade baryons. Comparing
the moments of the octet enables flavour symmetry breaking to be
explored. The simulations cover a wide range of the parameter
space in terms of the lattice spacing, pion mass and spatial volume,
enabling all sources of systematics to be controlled. In addition, we
give details of our determination of the third moment of the nucleon
spin structure functions and the twist-3 contribution.

Speaker: Sara Collins (University of Regensburg)

talk.pdf

10:00 AM Higher Mellin moments of the pion and kaon at the physical point

We will present our latest results on the second, third and fourth moments of the unpolarized PDF of the pion and the kaon using twisted mass fermion ensembles at the physical point. The reconstructed valence PDFs will be compared with phenomenological analyses.

Speaker: Constantia Alexandrou (University of Cyprus and The Cyprus Institute)

Trento-CA.pdf

10:30 AM → 11:15 AM Coffee Break

11:15 AM → 12:15 PM Session 2: Feng Yuan (Chair)

11:15 AM Probing quantum entanglement with generalized parton distributions

Within the collinear factorization framework based on Generalized Parton Distributions (GPDs), we calculate the spin density matrix of exclusively produced quark and antiquark pairs u\bar{u}, d\bar{d}, s\bar{s}, c\bar{c}, b\bar{b} in electron-proton scattering. The presence of both real and imaginary parts in the scattering amplitudes leads to a rich pattern of entanglement between the quark and the antiquark. We map out kinematical regions where the pairs exhibit entanglement, Bell nonlocality and non-stabilizerness (`magic'). We also predict that massive quarks and antiquarks are transversely polarized, similar to the well-known transverse hyperon polarization in unpolarized collisions. In strangeness, charm and bottom productions, the polarization can reach 50-80\% in certain kinematic regions in the low-energy runs of the Electron-Ion Collider.

Speaker: Yoshitaka Hatta (BNL)

hatta.pdf

hatta.pptx

11:45 AM Pressure-Energy Equations of State of Hadrons, Superconductor Vortices, and the Cosmos

The pressure–energy relations in the nucleon are derived from the gravitational form factors, which parameterize matrix elements of the energy-momentum tensor (EMT), together with EMT conservation. The static pressure distribution arising from the Lorentz trace part of the EMT, as manifested in the spatial stress $\frac{1}{3} T^{ii}$, equals minus the corresponding trace part of the energy density, which can be understood in terms of the gluon and quark condensates. It can be shown that this trace-anomaly- and sigma-term-induced pressure plays a fundamental role in the confinement dynamics of QCD. In contrast, the dynamic pressure distribution from the traceless part of the spatial stress tensor equals $1/d$ of the corresponding traceless part of the energy density, where $d$ is the spatial dimension. We point out that the same pressure–energy relations also hold for vortices in type-II superconductors, where the static pressure–energy relation originates from the Cooper-pair condensate. Furthermore, identical equations of motion appear in the $\Lambda{\rm CDM}$ model of cosmology, where the static pressure–energy relation arises from the cosmological constant.

Speaker: Prof. Keh-Fei Liu (Lawrence Berkeley National Lab)

12:15 PM → 1:45 PM Lunch break

1:45 PM → 4:30 PM Free afternoon

Thu, June 18

9:30 AM → 10:30 AM Session 1

9:30 AM Disconnected Sea, Low-x Dynamics, and 3D Hadron Structure

Using the framework of GPDs and related multidimensional QCD observables, we developed an interpretation of connected and disconnected contributions emerging from the ab-initio Euclidean path-integral formulation of QCD. We provide a common description of nucleon elastic form factors, parton distribution functions, while elucidating nonperturbative contributions to deep-inelastic and exclusive scattering observables. The framework can be extended to the low-x regime probing baryon transport, baryon-junction dynamics, and complex color-field topologies.

Speaker: Simonetta Liuti (University of Virginia)

Simonetta's talk

🤔 Thinking Face Emoji.htm

10:00 AM Generalized parton distributions with AI/ML methods

AI/ML techniques are particularly apt for addressing the inverse problems posed by the extraction of generalized parton distributions from experimental data and lattice QCD (LQCD) results. In the Exclusives in AI/ML (ExclAIm) collaboration, we lay the foundation for the application of such techniques with a spectator model-based parameterization of valence, sea, and gluon GPDs that offers predictions in the kinematics of Jefferson Lab and the upcoming Electron-Ion Collider. With this parametrization in hand, we benchmark our deep learning-based framework for the extraction of GPDs from Compton form factors and Mellin moments called NNGPD. In addition to deep learning methods, we have a distinct interest in interpretable AI/ML such as symbolic regression, which we have used to give a physical interpretation of GPDs from LQCD calculations.

Speaker: Zaki Panjsheeri (University of Virginia)

ZP_Trento2026.pdf

10:30 AM → 11:15 AM Coffee break

11:15 AM → 12:45 PM Session 2

11:15 AM Moments of Light-Cone Distribution Amplitudes from Lattice QCD

Generalized parton distributions (GPDs) and light cone distribution amplitudes (LCDAs) are central for the understanding of hard exclusive processes. In collinear factorization, LCDAs correspond to lightfront wavefunctions, while parton distribution functions (PDFs) have a probabilistic interpretation, within the parton model limit. We present results for the lowest Mellin moments of meson and baryon LCDAs, which give us insight into the longitudinal structure of these hadrons. A complementary approach is the "direct" computation of these non-perturbative objects from non-local currents or current-current correlations within hadrons at large spatial momenta. If time permits, I will briefly discuss this approach.

Speaker: Gunnar Bali

bali_ectstar.pdf

11:45 AM Evolution of pion-nucleon transition distribution amplitudes

Transition distribution amplitudes (TDAs) are non-perturbative functions that emerge within the collinear factorized description of hard exclusive scattering processes involving the exchange of a non-zero baryon number. TDAs provide new information that complements and extends the insights provided by other non-perturbative quantities, such as generalized parton distributions and distribution amplitudes. The goal of our work is the implementation of QCD evolution equations for a specific set of TDAs, namely the nucleon-to-pseudoscalar meson TDAs. While these equations are theoretically well-established, their computation has been limited by their structural complexity and by the difficulties in developing a stable numerical implementation.
The project aims to resolve these issues by utilizing a polynomial basis expansion for TDAs. This method significantly simplifies the numerical implementation while maintaining a reliable description of the evolved functions.
A key feature of this approach is its flexibility, since it is straightforward to adopt different polynomial bases to better approximate specific models. Furthermore, the evolution procedure remains largely independent of the intrinsic complexity of the model, as the evolution operators act directly on the polynomial basis rather than on the full TDA.

Speaker: Arianna Vercesi

ECTjune26_VercesiA.pdf

12:15 PM Higher PDF moments from lattice QCD with gradient-flowed operators

Lattice QCD can provide complementary first-principles information for global analyses through Mellin moments of parton distribution functions. In this talk I will discuss a lattice-QCD approach based on gradient-flowed twist-two operators for the calculation of PDF moments, with particular emphasis on the possibility of accessing higher moments.

The gradient flow provides a useful way to define renormalized composite operators at positive flow time. By exploiting continuum symmetries at finite flow time, one can construct flowed operators for arbitrary moments that are free from power-divergent mixing. I will describe the main ingredients of this strategy, its advantages for the computation of higher moments, and the associated sources of systematic uncertainty. I will also discuss recent progress and prospects for using flowed moments as quantitative lattice input for phenomenology.

Speaker: Andrea Shindler (RWTH -- Aachen University)

shindler_flowmom.pdf

12:45 PM → 2:15 PM Lunch break

2:15 PM → 3:15 PM Session 3: Andrea Shindler (Chair)

2:15 PM Gluon and flavor-separated contributions to hadron structure

The calculation of gluonic and flavor-separated contributions to the structure of the nucleon and pion is considerably more computationally demanding than that of the isovector contributions. In this talk, I present recent work by the Hadstruc Collaboration aimed at computing gluonic contributions to the one-dimensional PDFs of the nucleon, and preliminary work on the gluonic contributions to the pion. The calculations exploit a compendium of approaches aimed at variance reduction, including the use of distillation and gradient flow. I conclude with an analysis of the flavor-separated quark PDFs of the nucleon, and describe the implications of the calculations for future studies of GPDs.

Speaker: David Richards (Jefferson Lab)

trento06182026.pdf

2:45 PM Mellin Moments of the Unpolarized Gluon PDF in the Proton from Nonlocal Operators

We present a lattice QCD determination of the Mellin moments of the unpolarized gluon parton distribution function in the proton extracted from matrix elements of nonlocal gluon operators coupled to momentum-boosted proton states. The calculation is performed on an $N_f=2+1+1$ ensemble of maximally twisted mass fermions with clover improvement and the Iwasaki-improved gauge action, at a pion mass of approximately 260 MeV. Working within the short-distance operator product expansion (OPE) of the reduced gluon Ioffe-time distribution, we extract ratios of higher-order gluon moments, $\langle x^n\rangle$ with $n>1$, to the gluon momentum fraction, $\langle x\rangle$. We investigate systematic effects associated with the truncation of the order of moment in the OPE, the choice of minimum and maximum Wilson-line separations entering the analysis, and the treatment of mixing with the quark-singlet under perturbative matching. The stability of the extracted moments is further studied under scale evolution using DGLAP equations, allowing us to assess uncertainties related to perturbative truncation by varying the scale. Our work provides a determination of the ratio $\langle x^3\rangle_g/\langle x\rangle_g$ at a scale of 2 GeV, with uncertainties that account for both statistical and the dominant theoretical systematic uncertainties.

Speaker: Joseph Delmar (Argonne National Laboratory)

3:15 PM → 3:45 PM Coffee Break

3:45 PM → 4:15 PM Session 4: Andrea Shindler (Chair)

8:00 PM → 10:00 PM Workshop Dinner: Restaurant DUE MORI Via San Marco 11, Trento

Restaurant DUE MORI Via San Marco 11, Trento

Fri, June 19

9:30 AM → 10:30 AM Session 1

9:30 AM Gluon Wigner Distributions in boost-invariant longitudinal position space

The Wigner distributions (WDs) in boost-invariant longitudinal space for unpolarized, longitudinally polarized and linearly polarized gluons within a proton are presented in the framework of the light-front gluon spectator model inspired by AdS/QCD. The boost-invariant longitudinal space defined by the coordinate $\sigma=\frac{1}{2}b^- P^+$, can be accessed through the Fourier transformation over skewness $\xi$ to the gluon-gluon correlator of generalized transverse momentum dependent distributions (GTMDs).
The model results for gluon WDs in $\sigma$-space show an oscillatory behavior analogous to the diffraction scattering of a wave in optics. The diffraction pattern is more sensitive to the momentum fraction $x$ and passively varies with the total energy transfer to the electron-proton scattering $-t$, both of which are analogous to an effective slit-width. The leading-twist gluon WDs in the impact-parameter space and their skewness sensitivity are investigated extensively for unpolarized, longitudinally polarized, and transversely polarized protons. The gluon spin-OAM correlation is also reported and compared with existing models and lattice results.

Speaker: Tanmay Maji (Department of Physics, National Institute of Technology Kurukshetra, India)

3DTromgraphy_WD_ECT_19June26_Re.pdf

10:00 AM Connecting baryon light-front wave functions to quasi-transverse-momentum-dependent correlators in lattice QCD

Within light-front quantization, hadrons can be represented on a Fock-space basis of configurations of elementary partons. The coefficients of the expansion are called light-front wave functions (LFWFs), and encode all the dynamical degrees of freedom. We show how to extract the LFWFs of baryons, such as the proton, from equal-time correlators suitable for Lattice QCD simulations. Using an operator product expansion, we prove the factorization of the relevant correlator in the three-quark color-singlet LFWF, a residual lattice factor, and a soft factor that systematically subtracts the additional divergences arising from the factorization. We verify up to next-to-leading order the independent renormalizability of the LFWF, and we derive the evolution equations that govern its scale dependence.

Speaker: Andrea Schiavi (Università degli Studi di Pavia and Istituto Nazionale di Fisica Nucleare, Sezione di Pavia)

aschiavi_baryon_lfwf_to_lattice.pdf

10:30 AM → 11:00 AM Coffee Break

11:00 AM → 11:30 AM Discussion

11:30 AM → 11:45 AM Closing

11:45 AM → 12:45 PM Farewell Lunch