QCD Evolution 2025

May 19, 2025, 8:00 AM → May 23, 2025, 5:00 PM US/Eastern

CEBAF Center, Auditoriium (Jefferson Lab)

Nobuo Sato (Jefferson Lab), Alexei Prokudin (JLab)

QCD Evolution 2025 will be held at Jefferson Lab, Newport News, VA, USA on May 19- May 23, 2025. 

The QCD Evolution workshop series started in 2011. Since this initial meeting, QCD Evolution has grown to be a leading hadron physics meeting with a focus on hadron tomography.

The main objective of the QCD Evolution Workshop is to provide a forum to discuss the recent scientific accomplishments in areas such as generalized parton distributions (GPDs), transverse momentum distributions (TMDs), and small-x physics, together with advances in perturbative and non-perturbative techniques within QCD, such as lattice QCD and effective field theory (EFT) techniques.

In doing so this workshop also aims to support and guide the physics programs at facilities such as Jefferson Lab, the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab, Fermi National Accelerator Laboratory, and the Large Hadron Collider (LHC) complex at CERN. The workshop is also central to the building of the next-generation nuclear physics facility in the US, the Electron Ion Collider (EIC).

The Local Organizing Committee:

• Nobuo Sato (JLab, Chair)
• Joseph Karpie (JLab) 
• Wally Melnitchouk (JLab)
• David Richards (JLab)
• Marco Zaccheddu (JLab)
• Zhite Yu (JLab)

The International Advisory Committee: 

Alessandro Bacchetta (Pavia), Ian Balitsky (ODU and JLab), Daniel Boer (Groningen), Elena Boglione (Turin), Ian Cloet (ANL), Martha Constantinou (Temple), Umberto D'Alesio (Cagliari),  Leonard Gamberg (PSU Berks), Yoshitaka Hatta (BNL), Zhongbo Kang (UCLA), Yuri Kovchegov (OSU), Asmita Mukherjee (IIT Bombay), Barbara Pasquini (Pavia), Alexei Prokudin (PSU Berks and JLab), Jianwei Qiu (JLab), Anatoly Radyushkin (ODU and JLab), Ivan Vitev (LANL), Feng Yuan (LBNL).

Please, send your questions and inquiries about the event to qcd_evolution2025@jlab.org.

 

Mon, May 19

8:50 AM → 9:00 AM Welcome

9:00 AM → 10:30 AM Plenary

9:00 AM TBA

Speaker: Zein-Eddine Meziani (Argonne National Laboratory)

9:30 AM Proton GPDs from Lattice QCD at Leading Twist and Beyond

Speaker: Martha Constantinou (Temple University)

10:00 AM TBA

Speaker: George Sterman (SBU)

10:30 AM → 11:00 AM Coffee

11:00 AM → 12:00 PM Plenary

11:00 AM Latest Developments in the Theory of Multi-Hadron Fragmentation Functions

High-energy collision processes where multiple hadrons are detected in the final state provide a rich structure to probe QCD dynamics. Establishing the correct quantum field-theoretic operator definition of multi-hadron fragmentation functions is critical in this regard. I will discuss the latest developments in the theory of multi-hadron fragmentation functions in interpreting them as number densities and deriving their associated evolution equations as well as their connection to factorization formulas.

Speaker: Daniel Pitonyak (Lebanon Valley College)

11:30 AM Resummation of Flattened Jet Angularity Using Soft-Collinear Effective Theory

Jet angularity is a classic substructure observable which probes the angular distribution of jet constituents. While soft-drop grooming may suppress complicated contributions from wide-angle, soft radiation, the dependence on jet algorithm also limits the theoretical precision to higher accuracy. In this work we provide resummed calculations of flattened jet angularity which generalizes the power-law angular weight to generic functions using soft-collinear effective theory. This observable provides a new and flexible way of probing jet substructure phase space with applications in boosted particle tagging and hard probes of nuclear matter.

Speaker: Yang-Ting Chien (GSU)

12:00 PM → 2:00 PM Lunch

2:00 PM → 3:30 PM Parallel I

2:00 PM Addressing the Deconvolution Problem in DVCS Through String-Based GPDs

Generalized parton distributions (GPDs) are accessible through experimental processes such as deep virtual Compton scattering (DVCS) and deep virtual meson production (DVMP). Extracting GPDs directly from Compton form factors is complicated by the inherent ambiguity of deconvolution when parametrizing GPDs directly in momentum fraction $x$-space using double distributions. To overcome this challenge, we propose parametrizing GPDs via conformal moments in $j$-space, which naturally satisfy the polynomiality condition mandated by Lorentz invariance and offer a clear physical interpretation in terms of spin-$j$ resonance exchanges in the $t$-channel. In this talk, which is based on PRL.133.241901 (2024) and PRD.110.114016 (2024), we introduce a novel string-inspired parametrization for nucleon quark and gluon GPDs, applicable across all skewness $\xi$. Our framework expresses conformal moments explicitly as combinations of skewness-independent nucleon spin-$j$ A-form factors and skewness-dependent nucleon spin-$j$ D-form factors. These structures emerge naturally from $t$-channel string exchanges within an anti-de Sitter (AdS) space, ensuring consistency with Lorentz invariance and unitarity. Leveraging empirical Mellin moments from existing parton distribution functions (PDFs), our approach establishes a unique mapping between conformal moments in $j$-space and GPDs in momentum fraction $x$-space at arbitrary skewness.

Speaker: Kiminad Mamo (William and Mary)

2:30 PM TBA

Speaker: Jakob Schoenleber (Brookhaven National Laboratory)

3:00 PM TBA

We extend the formalism of Phys.Rev.Lett. 133 (2024) 24, 241901 to helicity generalized parton distributions (GPDs) with the skewness dependence modeled by t-channel exchanges of spin-j operators in AdS space. Based on the conformal moment expansion, the GPDs are obtained through Mellin-Barnes integrals which bypass the convolution problem and are valid for all values of the skewness parameter. With a minimal set of free parameters and the helicity parton distribution functions (PDFs) from the Asymmetry Analysis Collaboration (AAC) as an input, we predict the functional dependence of the conformal moments which enables us to construct the isoscalar, isovector, flavor separated and singlet quark and gluon helicity GPDs. Additionally, we compute the impact parameter representation of the associated helicity, angular momentum and spin-orbit contributions of the valence and sea constituents, enabling a full tomographic analysis of the proton spin decomposition.

Speaker: Florian Hechenberger (Stony Brook University)

2:00 PM → 3:30 PM Parallel II

2:00 PM Quark and Gluon GPD Global Analysis with DVCS and DVMP at NLO

We use the GUMP (Generalized Parton Distributions (GPDs) through Universal Moment Parametrization) framework, based on the conformal moments of GPDs, to perform a unified global analysis incorporating Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) data. By performing simultaneous fits across these processes and incorporating Next-to-Leading Order (NLO) corrections, we are able to constrain the valence quark, sea quark and gluon GPDs.

Speaker: Fatma Aslan (JLab)

2:30 PM Progress towards the extraction of GPDs utilizing machine learning

I will present recent progress on the extraction of GPDs from data utilizing machine learning.

Speaker: Eric Moffat (Argonne National Lab)

3:00 PM Likelihood Analysis of Helicity Configurations from Deeply-Virtual Compton Scattering Experiments

There is a wealth of information encoded in Generalized Parton Distributions (GPDs) to describe the three-dimensional structure of the nucleon. Deeply Virtual Compton Scattering (DVCS) experiments play a crucial role in accessing these distributions, providing a direct link to the spatial and momentum structure of partons inside the nucleon. The DVCS cross-section is commonly expressed either in terms of Compton Form Factors (CFFs) or helicity amplitudes, with the latter offering a more explicit representation of the helicity structure of the scattering process. In this presentation, I will discuss the formalism of photon electroproduction in terms of helicity amplitudes and the extraction of these amplitudes from DVCS experiments using likelihood analysis. This approach enables a statistically robust determination of helicity configurations by incorporating experimental uncertainties and correlations.

Speaker: Kemal Tezgin

3:30 PM → 4:00 PM Coffee

4:00 PM → 5:00 PM Parallel I

4:00 PM Zero Mode Issue in the Minus-Minus Component Calculation of the Meson-Photon Transition Form Factors in the Light-Front Dynamics

Zero mode issue in the minus-minus component calculation of the transition form factors in the light-front dynamics Among the three forms of Hamiltonian dynamics Dirac proposed in 1949, the light-front dynamics (LFD) has the most kinematical Poincare operators. In particular, the longitudinal boost operator becomes kinematical in the LFD. The LFD has very distinct vacuum properties, leading to its zero-mode issue which complicates calculations. The minus components in the LFD, related to higher-twist terms in the PDF and GPD formulations, have been notoriously difficult to calculate. In this talk, I will discuss the "minus-minus" component of the transition amplitude in the meson to two photon process, and discuss the role light-front zero-modes play. I will show the existence of spurious form factors, and that they cancel when the light-front time-ordered diagrams are summed. I will discuss the implication of this toy calculation for the GPD formulation.

Speaker: Bailing Ma (Argonne Natioinal Lab)

4:30 PM D-term and Dispersion Relations beyond Kinematic Twist-4

Quantum Chromodynamics (QCD) is the theoretical framework to study hadrons by means of their fundamental degrees of freedom, i.e.~quarks and gluons, collectively referred to as partons. QCD defines many types of distributions describing a given hadron in terms of partons. For the purposes of this talk, we are interested in the so-called generalized parton distributions (GPDs) which are off-forward matrix elements of quark and gluon operators and are typically accessed in exclusive Compton scattering. Convolutions of GPDs with coefficient functions describing the interaction of photons with the partons in the hadron are named Compton form factors (CFFs). Real and imaginary parts of CFFs are related by subtracted'' dispersion relations, i.e.~the difference between the real and imaginary parts is given by a constant. This subtraction constant can be written by means of the so-called $D$-term, which is one of the functions that parameterize the GPDs. The $D$-term is of special interest in hadron physics as it is the bridge connecting the subtraction constant (accessible in experiments by measurements of the CFFs) to the internal distribution of pressure in the hadron. The latter is given the gravitational form factor (GFF) $C$. These GFFs are functions which parameterize the QCD energy-momentum tensor and can be related tomechanical'' properties of the hadron such as mass, pressure or shear forces. In this talk, we propose a dispersion relation valid to all-orders in perturbation theory and up to kinematic twist four accuracy in order to study the $D$-term and its implications in the subtraction constant and the pressure inside the hadron.

Speaker: Victor Martinez-Fernadnez

4:00 PM → 5:00 PM Parallel II

4:00 PM Probing the Proton's Correlated Spatial Structure Through Exclusive Processes

Generalized parton distributions (GPDs) serve as indispensable tools in filling in the gaps of the angular momentum sum rules as well as mapping the partonic spatial structure of hadrons. In this work, we extend the utility of GPDs in mapping the proton’s spatial structure beyond the typical one-body partonic picture, obtainable through Fourier transformations of GPDs to impact parameter space. Connecting two-body densities with the correlation functions that define double GPDs, we find that exclusive processes give access to relative distances and overlaps between partons.

Speaker: Panjsheeri Zaki

4:30 PM TBA

We compute the contribution of the quark and gluon component of the energy-momentum tensor (EMT) to the angular momentum density in various decompositions. We use the light-front Hamiltonian technique, and a two-component formalism in light-front gauge, where the constrained degrees of freedom are eliminated. Instead of a nucleon, we consider a simple composite spin-1/2 state, namely a quark dressed with a gluon. We present two-dimensional light-front distributions in transverse impact parameter space and compare the different angular momentum decompositions at the density level. We also verify the spin sum rule for such a state.

Speaker: Singh Ravi

Tue, May 20

9:00 AM → 10:30 AM Plenary: Plenay

9:00 AM Perturbative Corrections to Quark TMDPDFs in the Background-Field Method

I'll discuss calculation of the NLO corrections to the unpolarized quark TMDPDFs using the factorization scheme defined in arXiv:2311.16402. The scheme aims to take into account the all collinear twist content of the TMDPDFs in the region of large $b_\perp\lesssim\Lambda^{-1}_{QCD}$ and bridge together the limits of large and small-x. I'll discuss different aspects of this derivation including the role of the QCD equations of motion.

Speaker: Andrey Tarasov (North Carolina State University)

9:30 AM Rapidity Factorization and Rapidity Evolution in QCD

Speaker: Ian Balitsky (JLab/ODU)

10:00 AM TBA

Speaker: Yuri Kovchegov (The Ohio State University)

10:30 AM → 11:00 AM Coffee

11:00 AM → 12:30 PM Plenary

11:00 AM Status of the Simultaneous Global Analysis of PDFs and TMDs

Speaker: Patrick Barry (Argonne National Lab)

11:30 AM First Neural-Network Extraction of Unpolarized Transverse-Momentum-Dependent Distributions

We present the first extraction of transverse-momentum-dependent distributions of unpolarized quarks from experimental Drell-Yan data using neural networks to parametrize their nonperturbative part. We show that neural networks outperform traditional parametrizations providing a more accurate description of data. This work establishes the feasibility of using neural networks to explore the multi-dimensional partonic structure of hadrons and paves the way for more accurate determinations based on machine-learning techniques.

Speaker: Chiara Bissolotti (Argonne National Laboratory)

12:00 PM TBA

12:30 PM → 2:00 PM Lunch

2:00 PM → 3:30 PM Parallel I

2:00 PM Imaging Bound Nucleons

In this talk, I will discuss recent advances in our ability to image parton distribution functions (PDFs) in bound nucleons. I will review topics from last year’s QCD Evolution workshop, such as methods for extracting nuclear-modified PDFs and TMDs. Additionally, I will discuss perturbative approaches that show how the evolution of TMD PDFs in Drell-Yan (p+A) collisions follows a BFKL evolution equation, arising from interactions between the collinear mode and the anti-collinear medium. I will also explore how these methods can be used to study TMD fragmentation functions (FFs) in semi-inclusive deep-inelastic scattering (SIDIS) with nuclei. Finally, I will discuss how these techniques can be generalized to other PDFs and how they can aid in imaging the properties of a Quark-Gluon Plasma.

Speaker: John Terry (Los Alamos National Lab)

2:30 PM Probing Hadron Structure and Hadronization at Colliders Using Chiral Effective Theory

Speaker: Marston Copeland (Duke University)

3:00 PM TBA

Speaker: Leonard Gamberg (Penn State Berks)

2:00 PM → 3:30 PM Parallel II

2:00 PM TBA

Speaker: Matteo Cerutti (Hampton University and Jefferson Lab)

2:30 PM Towards a Pixel-Based Imaging of TMDs Distribution Functions

Speaker: Marco Zaccheddu (Jefferson Lab)

3:00 PM Energy Independence of the Collins Asymmetry in pp Collisions at STAR

Study of the origin of transverse single-spin asymmetries has triggered the development of the twist-3 formalism and the transverse-momentum-dependent parton distribution functions (TMDs). Measurement of the azimuthal distribution of identified hadrons within a jet in transversely polarized hadronic interactions provides an opportunity to study the TMD physics in the final state, {\it i.e.}, the Collins effect, which involves the convolution of the quark transversity with the Collins fragmentation functions. Significant discrepancies have been observed between experimental measurements of the Collins effect and theoretical predictions. Further precise measurements of the Collins effect can provide new insights into the three-dimensional structure of the proton. STAR experiment at RHIC has reported precision measurements of Collins asymmetries from jet + $\pi^{\pm}$ production in transversely polarized ${pp}$ collisions at a center-of-mass energy of $\sqrt{s}$ = 200 GeV. The STAR experiment reports high precision measurements of the Collins asymmetries for $\pi^{\pm}$ within jets from transversely polarized ${pp}$ collisions at $\sqrt{s}$ = 510 GeV. With energy-scaled jet $x_T$= $2p_T/\sqrt s$, a remarkable consistency is observed for Collins asymmetries of $\pi^{\pm}$ between 200 GeV and 510 GeV. This indicates that the Collins asymmetries are nearly energy independent, with at most a very weak scale dependence, in $pp$ collisions. This energy independence is significantly contrast to predictions that TMD evolution of the Sivers function leads to a substantial suppression of TSSA for $W^{\pm}$ production. These results extend to high momentum scales ($Q^2$ up to 3400 GeV$^2$) and enable unique tests of evolution and universality in the transverse-momentum-dependent formalism, thus providing important constraints for the Collins fragmentation functions.

Speaker: Yixin Zhang (Shandong University)

3:30 PM → 4:00 PM Coffee

4:00 PM → 5:00 PM Parallel I

4:00 PM Kinematic power corrections in TMD factorization

I will present the study of the DY and SIDIS structure functions within the TMD factorization theorem with the inclusion of Kinematic Power Corrections (KPCs). This new theory allows the description of previously theoretically inaccessible parts of the cross-section in a Lorentz invariant manner using only twist-two TMD distributions. Examples of application include Drell-Yan angular distributions and the Lam-Tumg relation, and the subleading SIDIS structure functions FUU,T and FUU,L. The impact of these corrections to the present and future SIDIS measurements is discussed.

Speaker: Sara Piloneta

4:30 PM Effect of TMD Shape function at low transverse momentum in $J/\psi$ photo- and electro-porduction

A proper transverse momentum-dependent (TMD) factorization for quarkonium production at low transverse momentum necessitates the convolution of the TMD parton distribution function (TMDPDF) with an additional transverse momentum-dependent function, known as the TMD shape function (TMDShF). We present a phenomenological study of the impact of the TMDShF on quarkonium production in electron-proton collisions, comparing our results with predictions from the standard nonrelativistic QCD (NRQCD) framework. Our analysis demonstrates that the inclusion of the TMDShF provides a qualitative explanation for the HERA data, particularly at low transverse momentum, where standard NRQCD predictions fail. Furthermore, we discuss the implications of a proper treatment of the TMDShF for the extraction of long-distance matrix elements (LDMEs) in the low-to-intermediate transverse momentum regime.

Speaker: Raj Kishore (IIT Bombay)

4:00 PM → 5:00 PM Parallel II

4:00 PM New Insights into Lambda Fragmentation Functions

In this talk I present a new determination of the unpolarised fragmentation functions (FFs) for Lambda production from single-inclusive e+e- annihilation, semi-inclusive deep-inelastic scattering and pp collisions data. The analysis is done at both next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). We extract the unpolarised FFs defining a parametrisation in terms of a neural network and determine their uncertainties with a Monte Carlo sampling method.

Speaker: Alessia Bongallino (Universidad del País Vasco UPV/EHU)

4:30 PM TBA

Speaker: Filippo Delcarro (University of Pavia)

Wed, May 21

9:00 AM → 10:30 AM Plenary

9:00 AM Connecting Theory to Experiment and Event Generator Development for Hard Exclusive Reactions

I would like to present recent work done for developing an event generator aimed at making projections for hard exclusive reactions such as Compton-like reactions and meson production, for JLab to EIC energies. We extended our framework to include new reactions (phi, gamma-meson...), radiative corrections, etc. In this talk we also would like to discuss the connections between this work and the use of AI/ML tools to duplicate these simulations for systematic studies of error propagation in Compton Form Factor fits. Finally, we will show projections for observables measurable in near-coming JLab experiments, and our impact studies on how CFF fits will be improved provided these new measurements in a multichannel approach.

Speaker: Marie Boer (Virginia Tech)

9:30 AM Quantum Anomaly and GPDs

Speaker: Shohini Bhattacharya (University of Connecticut)

10:00 AM Proton Gravitational Form Factors with Threshold Heavy-Quarkonium Production at NLO

I will discuss some recent progresses in constraining the gravitational form factors (GFFs) of the proton via near-threshold heavy quarkonium production with next-to-leading order alpha_S corrections. Particularly, I will show with Bayesian inference that such processes provide important constraint on the gluonic GFFs as well as the quark GFFs whose contributions emerge at next-to-leading order.

Speaker: Yuxun Guo (Lawrence Berkeley National Lab)

10:30 AM → 11:00 AM Coffee

11:00 AM → 12:30 PM Plenary

11:00 AM Reframing Azimuthal Modulations in Hard Exclusive Diffraction Processes

I am going to present a new formulation of the azimuthal modulations in hard exclusive diffraction processes. These are crucial in the phenomenological extraction and separation of various generalized parton distributions (GPDs). Traditionally, GPDs could be extracted from angular modulations of the deeply virtual Compton scattering (DVCS) in the Breit frame. However, the Bethe-Heitler subprocess (BH) interferes with the DVCS and contaminates the azimuthal modulations from DVCS, making it challenging to extract GPDs cleanly. We provide a new formalism and choice of frame to describe the azimuthal distributions, and demonstrate that they are more suitable for experimental analysis to separate contributions to a physical cross section from GPD sensitive (such as DVCS) and insensitive (e.g., BH) subprocesses in a consistent and uniform way.

Speaker: Zhite Yu (Jefferson Lab)

11:30 AM TBA

Speaker: Swagato Mukherjee (Brookhaven National Laboratory)

12:00 PM Perturbative Results of the Axial Current and the Axial Anomaly

In the Standard Model of particle physics, the axial current is not conserved, due both to fermion masses and to the axial anomaly. Using perturbative quantum chromodynamics, we calculate matrix elements of the local and non-local axial current for a gluon target, clarifying their connection with the axial anomaly. In so doing, we also reconsider classic results obtained in the context of the nucleon spin sum rule as well as recent results for off-forward kinematics. An important role is played by the infrared regulator, for which we put a special emphasis on the nonzero quark mass. We highlight cancellations that take place between contributions from the axial anomaly and the quark mass, and we elaborate on the relation of those cancellations with the conservation of angular momentum. Furthermore, we discuss the connection of related recent publications and our work.

Speaker: Andreas Metz (Physics Department, Temple University, Philadelphia)

12:30 PM → 2:00 PM Lunch

2:00 PM → 5:00 PM Excursion

Thu, May 22

9:00 AM → 10:30 AM Plenary

9:00 AM TBA

Speaker: Joe Karpie

9:30 AM tiktaalik: Code for Ultra-Fast GPD Evolution

Generalized parton distributions (GPDs) are functions of four variables, one of which is a renormalization scale. The functional dependence on this renormalization scale is fully determined by a renormalization group equation---or "evolution equation"---that can be derived from perturbative QCD. A fast numerical implementation of the scale evolution is vital to any global phenomenology effort. Moreover, for a framework leveraging neural networks, differentiability is also necessary. In this talk, I will discuss an ultra-fast, differentiable implementation of GPD evolution in momentum fraction space, in which the evolution equation itself is (approximately) rendered as a differential matrix equation.

Speaker: Adam Freese (Jefferson Lab)

10:00 AM Investigating the Transverse Structure of Hadrons Using Parton Pseudodistributions

Within the pseudo-PDF framework, we investigate the perturbative contributions to correlators that are used to study transverse momentum dependent parton distributions (TMDs) on the lattice. Our results contain the full perturbative corrections which arise as artifacts from performing the calculation for a Euclidean separation between the parton fields, as well as the corrections which yield the evolution equations for the TMDs.  This gives a path to extraction of the genuine non-perturbative features of the three-dimensional structure of the hadrons from lattice calculations.

Speaker: Gabriel Santiago (Center for Nuclear Femtography)

10:30 AM → 11:00 AM Coffee

11:00 AM → 12:30 PM Plenary

11:00 AM TBA

Speaker: Bernd Surrow (Temple University)

11:30 AM TBA

A new global QCD analysis by the JAM collaboration performs the first extraction of transversity PDFs and tensor charges using both the Transverse Momentum Distribution (TMD) and Dihadron Fragmentation Function (DiFF) channels simultaneously, including all currently available experimental data. Known theoretical constraints on transversity, namely, its small-$x$ asymptotic behavior and the Soffer bound, are incorporated in the fit. We test compatibility with lattice-QCD calculations for the tensor charges by including them in the fit, in order to further examine whether there is a universal nature to all of the available information on transversity distributions and tensor charges of the nucleon.

Speaker: Christopher Cocuzza (College of William & Mary)

12:00 PM TBA

12:30 PM → 2:00 PM Lunch

2:00 PM → 3:30 PM Parallel I

2:00 PM TBA

Speaker: Michael Wagman (FNL)

2:30 PM TBA

Speaker: Daniel Kovner (William & Mary)

3:00 PM TBA

I will present on the extraction of disconnected contribution to the isoscalar matrix elements for light and strange quarks for the proton using Lattice QCD. While the connected contributions dominate the disconnected contributions are non-zero and must be considered to properly determine the matrix elements. In the case of the strange quark, there is no connected contribution, thus it is paramount to correctly measure these contributions.

Speaker: Christopher Chamness (The College of William & Mary)

2:00 PM → 3:30 PM Parallel II

2:00 PM Entanglement as a Probe of Hadronization

Speaker: Charles Joseph Naїm (Stony Brook University (CFNS))

2:30 PM TBA

Speaker: Etienne Bianco

3:00 PM Probing Hadronization and Quark-Gluon Plasma Using Collinear-Drop Jet Observables

Speaker: Oleh Fedkevych (Georgia State University)

3:30 PM → 4:00 PM Coffee

4:00 PM → 5:00 PM Parallel I

4:00 PM TBA

Speaker: Alexandru Sturzu

4:30 PM Parton Distributions from Boosted Fields in the Coulomb Gauge

Speaker: Xiang Gao (BNL&Tsinghua University)

4:00 PM → 5:00 PM Parallel II

4:00 PM Proton Spin from Small-x With Constraints from the Valence Quark Model

We apply the valence quark model to constrain the non-perturbative initial condition for the small-x helicity evolution. The remaining free parameters are constrained by performing a global analysis to the available polarized small-x deep inelastic scattering data. A good description of the world data is obtained with only 8 free parameters. The model parameters are tightly constrained by the data, allowing us to predict the proton polarized structure-function to be negative at small x. Furthermore, we obtain the small-x quark and gluon spins, depending on the applied running coupling prescription.

Speaker: Daniel Adamiak (Ohio State University)

4:30 PM TBA

We study the quark TMD in light cone gauge. Using the background field methods of Color Glass Condensate formalism we calculate the first perturbative corrections ( order $\alpha_s$) to quark TMD and derive the CSS evolution equation. We comment on the significance of using the correct prescription for the light cone gauge singularity in the gluon propagator.

Speaker: Jamal Jalilian-Marian (City University of New York, Baruch College)

Fri, May 23

9:00 AM → 10:30 AM Plenary

9:00 AM TBA

Speaker: Patrizia Rossi (Jefferson Lab)

9:30 AM Quasifragmentation Functions and Quasiparton Distributions in the Massive Schwinger Model

Speaker: Sebastian Grieninger (Stony Brook University)

10:00 AM TBA

I revisit the factorization of inclusive deep inelastic scattering near the kinematic threshold to explicitly track off-lightcone effects. Particle production develops around two opposite near-lightcone directions like in transverse-momentum-dependent processes, and the Collins-Soper kernel emerges as a universal function in the rapidity evolution of the relevant parton correlators. I clarify outstanding issues regarding soft radiation and rapidity divergences, and uncover a new way to calculate the Collins-Soper kernel on the lattice with collinear operators.

Speaker: Andrea Simonelli (ODU and JLAB)

10:30 AM → 11:00 AM Coffee

11:00 AM → 12:00 PM Plenary

11:00 AM Kinematic power corrections to DVCS to twist-six accuracy

We calculate $(\sqrt{-t}/Q)^k $ and $(m/Q)^k$ power corrections with $k\le 4$, where $m$ is the target mass and $t$ is the momentum transfer, to several key observables in Deeply Virtual Compton Scattering (DVCS). We find that the power expansion is well convergent up to $|t|/Q^2\lesssim 1/4$ for most of the observables, but is naturally organized in terms of $1/(Q^2+t)$ rather than the nominal hard scale $1/Q^2$. We also argue that target mass corrections remain under control and do not break QCD factorization for coherent DVCS on nuclei. These results remove an important source of uncertainties due to the frame dependence and violation of electromagnetic Ward identities in the QCD predictions for the DVCS amplitudes in the leading-twist approximation.

Speaker: Prof. Vladimir Braun (University of Regensburg)

11:30 AM TBA

Speaker: Yoshitaka Hatta (Brookhaven National Laboratory)

12:00 PM → 2:00 PM Lunch

2:00 PM → 3:00 PM Parallel I: Parallel

2:00 PM Partonic and nuclear dynamics through the CJ global analysis lens

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

2:30 PM TBA

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

2:00 PM → 3:00 PM Parallel II

2:00 PM TBA

Speaker: Carl Carlson (William & Mary)

2:30 PM TBA

Speaker: Andrei Afanasev (GWU)

3:00 PM → 3:30 PM Coffee

3:30 PM → 4:30 PM Parallel I

3:30 PM TBA

Inverse problems are ubiquitous in hadron structure and tomography, where accurately characterizing uncertainties is crucial for unraveling new physics hiding within these uncertainties. In this new precision era of QCD, it is vital to create a translation between our physics and next generation AI/ML algorithms, using tools such as evidential deep learning and information-theoretic metrics to capture and separate contributions from aleatoric, epistemic, and distributional uncertainties. My research focuses on deploying evidence-based machine learning methods to decode parton distribution functions (PDFs) while exploring the vast parameter space of phenomenological and beyond-the-Standard-Model scenarios. Incorporating physics observables such as lattice QCD constraints and experimental measurements within these AI/ML paradigms refines the fidelity of PDF extractions and deepens our understanding of non-perturbative QCD. Ultimately, this integrated approach pushes the frontier of hadron structure discovery, aligning cutting-edge AI/ML progress with emerging opportunities at existing and future experimental physics facilities such as the EIC.

Speaker: Brandon Kriesten (Argonne National Lab)

4:00 PM TBA

Speaker: Saraswati Pandey (Banaras Hindu University)

3:30 PM → 4:30 PM Parallel II: Plenary II

3:30 PM Quantum Algorithms for High Energy Evolution

Speaker: Shaswat Tiwari (North Carolina State University)

4:00 PM TBA

My work focuses on trying to understand the mechanical properties of nucleons, such as mass, angular momentum, pressure, and shear force distribution, in terms of their quark and gluon constituents. In this work, we calculate the pressure and shear force distributions using the matrix elements of the energy-momentum tensor, which can be parametrized in terms of gravitational form factors. We employ light-front wavefunctions of a quark state dressed with a gluon at one loop in QCD. This state serves as a perturbative model for a relativistic spin-1/2 composite system with gluonic degrees of freedom. The light-front Hamiltonian approach is utilized along with a two-component formalism in the light-front gauge to handle the constrained fields.

Speaker: Sudeep Saha

4:30 PM → 5:00 PM Plenary: closing