10th workshop of the APS Topical Group on Hadronic Physics

Apr 12, 2023, 8:00 AM → Apr 14, 2023, 6:30 PM US/Central

Minneapolis, Minnesota

Julia Velkovska (Vanderbilt University), Will Brooks (Universidad Técnica Federico Santa María)

10TH WORKSHOP OF THE APS TOPICAL GROUP ON HADRONIC PHYSICS

• 157 registered participants: in person and online
• 134 presentations: thanks for sharing your research with the community
• 6 plenary and 24 parallel sessions
Thank you to all participants, speakers, session chairs!

Next workshop:

11TH WORKSHOP OF THE APS TOPICAL GROUP ON HADRONIC PHYSICS
14-16 MARCH 2025 in Anaheim, CA
• Mark your calendars!

SEE YOU AT GHP2025!

 

The 10th biennial workshop of the APS Topical Group on Hadronic Physics (GHP2023)  provides great opportunities for nuclear and particle physicists to meet and discuss their common interests in hadronic interactions. The workshop precedes the in-person 2023 April Meeting of the American Physical Society (April 15-18, 2023) and will take place at the same venue.

Workshop topics include:

• Artificial intelligence and machine learning for hadron physics
• Electron Ion collider and other future initiatives
• Electroweak probes
• Extreme matter and neutron star collisions
• Hadrons in nuclei
• Hadron spectroscopy
• Hadron tomography
• Hadronization
• Heavy flavor and jet production
• Neutrino-hadron interactions
• New physics and discrete symmetry violation in hadron physics
• Nonequilibrium dynamics
• Nucleon and nuclear spin physics
• Origin of hadron mass
• Physics of the quark-gluon plasma
• Quantum information for hadron physics
• Small systems and collectivity
• Transverse and longitudinal structure of hadrons
• Ultraperipheral Collisions

Direct Deposit Form (8).pdf

GHP2023-Poster.pdf

GHP Meeting 2023 [12-14 April] - Parallel Sessions.pdf

Venue maps

Wednesday, April 12

8:20 AM → 10:30 AM Plenary Session: 1, Chair: Julia Velkovska

8:20 AM Welcome

A 10-minute welcome to the workshop.

Speaker: Julia Velkovska (Vanderbilt University)

GHP23Welcome.pdf

8:30 AM Hot and Cold QCD for the NP Long Range Plan

I will review the QCD Town Hall Meeting and White Paper, covering the achievements since the 2015 Long Range Plan and future prospects. I will discuss the recommendations and initiatives and the science behind them.

Speaker: Bjoern Schenke (Brookhaven National Lab)

QCD2023LRP_Schenke.pdf

9:00 AM Physics opportunities with the Electron Ion Collider

After decades of planning, the design and construction of a new Electron Ion Collider (EIC) are underway at the Brookhaven National Laboratory. This new versatile machine for studying fundamental properties of nuclear matter will map the emergence of nucleonic properties from the dynamical interactions of the dense partonic medium. In addition to flagship measurements addressing connections between the partonic interactions and nucleon properties such as mass and spin, the EIC will allow complete three-dimensional imaging of inner-nucleon structures in position and momentum space. The availability of a wide range of ion species at EIC will allow us to search for gluon saturation thresholds and explore if the saturation phenomena result in gluonic matter with universal properties in all systems. New insights will be revealed into the interactions of energetic partonic probes with nuclear medium and how the presence of such medium affects the hadronization process.

Speaker: Olga Evdokimov (University of Illinois Chicago)

2023_GHP_EIC_Evdokimov.pdf

9:30 AM Heavy Ions from RHIC to the EIC era

In this talk, I will review topics in heavy-ion physics at RHIC and the LHC which are related to the physics of the EIC. This includes recent work in understanding the initial state of protons and heavy nuclei, searching for saturation phenomena, and the use of ultra-peripheral collisions.

Speaker: Dennis Perepelitsa (University of Colorado Boulder)

dvp-GHP-4-12-2023.pdf

10:00 AM JLab physics program & future initiatives

Jefferson Lab physics program ddresses important topics in nuclear, hadronic, and electroweak physics, including nuclear femtography, meson and baryon spectroscopy, quarks and gluons in nuclei, precision tests of the standard model and dark sector searches. Selected topics of the ongoing scientific program of the 12 GeV CEBAF will be presented. Also a potential energy upgrade of the accelerator and its impact on scientific reach will be discussed.

Speaker: Patrizia ROSSI (Jefferson Lab)

ROSSI_talk.pdf

10:30 AM → 11:00 AM Break

11:00 AM → 12:30 PM Plenary Session: 2, Chair: Martha Constantinou

11:00 AM 2022 GHP Fellow: Hadron scattering from lattice QCD

Hadron scattering information can be accessed indirectly from lattice QCD by computing the spectrum of multi-hadron states and connecting to the infinite volume amplitudes via quantization conditions. This methodology was applied successfully for the two-hadron case to extract phase-shifts and resonance parameters. Only recently this methodology was extended to the three-hadron sector: both lattice QCD calculations and developing quantization conditions is more challenging in this sector. I review our results for two and three meson scattering and their connection with infinite volume amplitudes.

Speaker: Andrei Alexandru (The George Washington University)

hadron-scattering-from-latticeqcd.pdf

11:30 AM The generalized polarizabilities of the proton

A fundamental property of the proton involves the system's response to an external electromagnetic (EM) field. It is characterized by the EM polarizabilities that describe how easily the charge and magnetization distributions inside the system are distorted by the EM field and the generalized polarizabilities that map out the resulting deformation of the densities in a proton subject to an EM field. They reveal unique information regarding the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents together. Of particular interest is a puzzle in the proton's electric generalized polarizability that remains unresolved for two decades. This talk will offer an overview on this topic, the discussion of new results from JLab and of future prospects.

Speaker: Nikos Sparveris (Temple University)

Sparveris-GPs.pdf

12:00 PM Extracting the Proton’s Tensor Charge from QCD Phenomenology

The proton’s tensor charge, connected to internal quark transverse spin, is one of its fundamental properties. This quantity has garnered interest from various communities, being relevant for QCD phenomenology, ab initio studies (e.g., lattice QCD, Dyson-Schwinger), and low-energy beyond the Standard Model searches. In this talk I will review the current status of extractions of the proton’s tensor charge within QCD global analyses of transverse-spin sensitive data from various processes. I will also discuss agreements and tensions that exist between different approaches and outline future work that may help us to converge on the value of this critical quantity.

Speaker: Daniel Pitonyak (Lebanon Valley College)

Pitonyak_GHP2023_Plenary.pdf

12:30 PM → 2:00 PM Lunch break

2:00 PM → 3:35 PM Parallel Session: Baryons, Hyperons, Cascades, Chair: Bill Briscoe

2:00 PM Investigation of the $\Sigma^{0}$ Production Mechanism in p(3.5 GeV)+p Collisions

The production of $\Sigma^{0}$ hyperons in proton proton collisions at a beam kinetic energy of 3.5 GeV impinging on a liquid hydrogen target was investigated using data collected with the HADES setup. The total production cross section is found to be $\mathrm{\sigma (pK^{+}\Sigma^{0}) [\mu b] = 17.7 \pm 1.7 (stat) \pm 1.6 (syst)}$. Differential cross section distributions of the exclusive channel $\mathrm{pp \rightarrow pK^{+}\Sigma^{0}}$ were analyzed in the center-of-mass, Gottfried-Jackson and helicity reference frames for the first time at the excess energy of 556 MeV. The data support the interplay between pion and kaon exchange mechanisms and clearly demonstrate the contribution of interfering nucleon resonances decaying to $\mathrm{K^{+}\Sigma^{0}}$. The Bonn-Gatchina partial wave analysis was employed to analyse the data. Due to the limited statistics, it was not possible to obtain an unambiguous determination of the relative contribution of intermediate nucleon resonances to the final state. However nucleon resonances with masses around 1.710 $\mathrm{GeV/c^{2}}$ ($\mathrm{N^{*}(1710)}$) and 1.900 $\mathrm{GeV/c^{2}}$ ($\mathrm{N^{*}(1900)}$ or $\mathrm{\Delta^{*}(1900)}$) are preferred by the fit.

Speaker: Dr Waleed Esmail (GSI Helmholtzzentrum für Schwerionenforschung GmbH)

GHP-Waleed-Esmail.pdf

2:20 PM Towards the Discovery of First Strange Hexaquark with CLAS12

Quantum Chromo Dynamics (QCD) is our current best description of interactions between quarks and gluons. It not only predicts the existence of the well understood mesons (two-quark) and baryons (three-quark) it also predicts exotic Tetra, Penta and Hexaquark states.
Experiments taking place at Thomas Jefferson Lab in Virginia, USA using the upgraded CLAS12 detector system allows a detailed investigation of exotic hadron states. In our experiment electrons accelerated to an energy of 10.6 GeV scatter off either a liquid hydrogen or liquid deuterium target. Various interesting effects can be explored in these reactions, including production of exotic hadrons, such as hybrids, pentaquarks or hexaquarks, the latter being the subject of this research.
This talk will present the analysis of data recently collected at CLAS12, which provides the first search for the ds hexaquark, a particle with quark content uuudds or uuddds with the most promising decay channel is expected to be $ed\to e’K^+d_s\to e’K^+\Lambda n$. The results of the analysis were benchmarked utilizing more conventional reactions. First results on a ds search will be presented, through the lens of polarization of the Lambda. From theory and the analogous $d^*\to pn$ reaction, we know that a peak in polarization should be seen at the mass of the ds. The polarization measurement will be benchmarked with independent measurements of the $ep\to e'K^+\Lambda$ reaction.
Our experimental studies will be confronted with state-of-the-art theoretical calculations on ds branching ratios and partial widths. It will be demonstrated that the expected ds width is well within the measuring capabilities of the CLAS12 setup, regardless of the nature of the $d_s$ dibaryon (hexaquark or molecular). It will be shown that precise knowledge of the $d_s$ mass and width constrains its internal structure.

Speaker: Geraint Clash (university of york)

GHP_APS_gclash.pdf

2:40 PM Cross Section Analysis for Ξ(1530) in the reaction γp ->K+K+Ξ(1530)

Doubly strange, so-called cascade (𝛯) baryons, should be found in abundant numbers based on relativistic quark models yet few have been found experimentally. Finding, identifying and matching these states is one of the most important objectives in particle physics, the so-called missing resonance problem. My research centers on the 𝛯(1530), using Glue-X Phase-1 data, I was able to identify the excited cascade, and through symmetries of the strong interaction able to determine the total cross section for the excited cascade decaying into the 𝛯𝜋 decay mode.

Speaker: Brandon Sumner (Arizona State University)

GHP 2023F.pdf

3:00 PM Total cross section of Ξ(1820)*− in γp → K+K+Ξ*− at GlueX.

The SU(3) flavor symmetry in the quark model for baryons allows as many Ξ resonances as N∗ and ∆∗ combined. Only a handful of these states have been identified experimentally and among these states, only six states have three and four-star status according to PDG. The GlueX experiment, in Jefferson Lab’s Hall D using a photon beam of energies up to 12 GeV allows us to study the Cascade baryon spectrum. In this presentation, we present the preliminary cross section results for the photoproduction of Ξ(1820)∗− baryon in the reaction γp → K+K+Ξ∗− with Ξ∗− → K−Λ. We are presenting the results for the Phase -I GlueX data for the incident photon beam energy range 6.0 to 11.4 GeV. These are the first total cross section results for Ξ(1820)∗− in photoproduction.

Speaker: chandra Akondi (FSU)

Xi(1820)GHP2023.pdf

3:20 PM Role of the QCD spin-directed momentum transfer mechanism in pp and ep scattering polarized hyperon production

Spin dependent quark and gluon distributions can lead to distinctive features in the angular dependences and asymmetries from proton proton and electron proton scattering processes. Of particular interest are heavy quark production processes, wherein spin asymmetries of the heavy quarks, correlated with diquarks can reveal the underlying spin dependence. Hyperon production including heavy flavor hyperons with diquark spectators polarization asymmetries can be used as probes to both the underlying perturbative and non-perturbative QCD dynamics.

Speaker: simonetta liuti (university of virginia)

liuti_GHP_23.pdf

2:00 PM → 3:40 PM Parallel Session: Collective Phenomena, Chair: Björn Schenke

2:00 PM Properties of gluon fields at early times in relativistic heavy ion collisions from a proper time expansion

We present some analytic results that describe the gluon fields at very early times after a collision of relativistic heavy ions at proper time $\tau = 0$. We use a Colour Glass Condensate approach, and perform an analytic expansion in $\tau$. We calculate the transverse and longitudinal pressures and show that they move towards their equilibrium values of one third of the energy density. We find a significant correlation between the elliptic flow coefficient of the azimuthal momentum distribution and the spatial eccentricity, which indicates that the spatial inhomogeneity introduced by the initial geometry is effectively transmitted to the azimuthal distribution of the gluon momentum field, even at very early times. We calculate the angular momentum of the glasma and obtain results that are many orders of magnitude smaller than the initial angular momentum of two ions colliding with non-zero impact parameter. This indicates that most of the angular momentum carried by the valence quarks is not transmitted to the glasma. We calculate the momentum broadening parameter of a heavy quark probe, and show that the glasma plays an important role in jet quenching.

Speaker: Margaret Carrington (Brandon University)

APS-carrington-2023.pdf

2:20 PM Effects of Conservation Laws on Particle Correlations in Relativistic Nuclear Collisions

The grand canonical statistical ensemble is usually assumed when simulating particle emission from the Quark-Gluon Plasma fluid created in relativistic heavy-ion collisions. These simulations conserve energy and momentum on an event-average level. This talk investigates how event-by-event local energy and momentum conservation [1] introduces non-trivial multi-particle correlations in Au+Au collisions at the RHIC. We will focus on the effects of local momentum conservation on the final-state particle dipolar flow and its correlations with the other anisotropic flow coefficients.We will also study the effects of micro-canonical sampling on particle spectra and anisotropic flow in
small proton-nucleus collisions at RHIC and LHC.

[1] D. Oliinychenko and V. Koch, “Microcanonical Particlization with Local Conservation Laws,”
Phys. Rev. Lett. 123, no.18, 182302 (2019)

Speaker: Harvir Dhindsa (Wayne State University)

GHP_Dhindsa_Shen.pdf

2:40 PM Studying the Properties of the Quark-Gluon Plasma With Small and Large Collision Systems in a Bayesian Analysis Framework

We model the evolution of the Quark-Gluon Plasma (QGP) with a multi-stage model that includes (i) geometric initial state energy deposition, (ii) viscous relativistic hydrodynamics, and (iii) hadronic transport. We perform rigorous comparison with experimental data using Bayesian inference. We go beyond previous JETSCAPE Bayesian analyses of the soft sector by studying the three-dimensional structure of large and small nuclear collisions, combining measurements at both RHIC and LHC energies. We discuss closure tests and the related emulation uncertainty. The sensitivity of particular observables to the model parameters is explored and the constraining power of small system observables on the properties of the QGP is discussed. The optimal parameters attained are used to compare calculations with a range of small and large system data.

Speaker: Andi Mankolli (Vanderbilt University)

2023_GHP_Workshop_Presentation.pdf

3:00 PM (tbd)

3:20 PM (tbd)

2:00 PM → 3:40 PM Parallel Session: Data Science, Chair: Ramona Vogt

2:00 PM Deep learning models for deeply virtual exclusive processes

Deeply virtual exclusive reactions are theorized to be sensitive to the dynamics of bound partons in hadrons through 3D quantum mechanical phase space distributions - the generalized parton distributions; however, there are many steps in the analysis from experimental data to information on hadron structure. The FemtoNet framework was developed to analyze deeply virtual exclusive experimental data using physics-informed deep learning models in order to quantify information loss and reconstruction through the many inverse problems encountered. Simultaneously, the FemtoNet framework leverages a suite of uncertainty quantification techniques to separate epistemic (reducible) and aleatoric (irreducible) errors from the analysis and properly propagate experimental uncertainty. I will demonstrate what physics-informed deep neural networks are capable of in the context of reconstructing lost information from inverse problems in exclusive scattering experiments and give prospects for the future of such a program and consequences for an EIC.

Speaker: Brandon Kriesten (University of Virginia)

Deep learning models for deeply virtual exclusive processes.pdf

2:20 PM Polarized and unpolarized gluon parton distributions from lattice QCD and machine learning

Understanding the internal structure and dynamics of protons and neutrons, the complex many-body systems consisting of strongly interacting quarks and gluons is at the core of exploring the visible matter universe. Gluons, which serve as mediator bosons of the strong interaction, play a key role in the nucleon’s mass and spin structures. In contrast, understanding of the gluon distributions and their roles in hadron structures remains some of the most challenging but fundamental issues in nuclear and particle physics. In this talk, we focus on the first lattice QCD determination of the gluon helicity parton distribution function with numerical evidence toward disfavoring negative gluon polarization in the nucleon and also discuss the reliability of overly constrained model-based extraction of unpolarized gluon distribution from limited lattice data. Using several machine learning algorithms on the Euclidean correlation functions, we demonstrate how one can alleviate the defining challenge of extracting quark-gluon PDFs from lattice data and point toward some critical future applications.

Speaker: Raza Sufian (University of Kentucky)

Sufian_GHP.pdf

2:40 PM GPU-based Online Reconstruction for J/$\psi$ TSSA at SpinQuest experiment

The E1039/SpinQuest experiment at Fermilab will measure the transverse single spin asymmetry (TSSA) in several processes such as J/$\psi$ production and Drell-Yan di-muon pair production, exploiting the 120 GeV unpolarized proton beam from the Fermilab Main Injector on transversely polarized fixed targets of NH$_3$ and ND$_3$. Such measurements are anticipated to provide knowledge on the Sivers function from the proton sea quarks and gluons. The Sivers function represents the correlation between the transverse momentum of a quark/gluon and the spin of the parent nucleon and gives hints about the orbital angular momenta of quarks and gluons, which are suspected to contribute significantly to the nucleon spin and thus are essential to solving the “proton spin puzzle”. In pursuit of these asymmetry measurements, we have developed an online reconstruction algorithm exploiting the high throughput and mass parallelization capabilities of graphics processing units (GPU), which combined with adequate visualization tools will provide real-time data monitoring for the SpinQuest experiment.
This talk will highlight the SpinQuest experiment and the projected measurements, uncertainties and efficiency studies for the J/$\psi$ TSSA from its first production data. The performance metrics of the GPU-based online reconstruction algorithm will also be discussed, along with the features and methods employed to reach successful real-time data visualization.

Speaker: Dr Eric Fuchey (mississippi state university)

GHP_talk_EFuchey.pdf

3:00 PM Developing an AI Tracking for the CLAS12 ALERT Program

A series of experiments were proposed to study the fundamental structure of light nuclei, such as $^{2}{H}$ and $^{4}{He}$. The program focuses on the exploration of the nuclear Generalized Parton Distributions (GPDs), EMC effects, as well as the nature and origin of nuclear effects. The key feature of these measurements is the challenging detection of the low-momentum recoil particles in a large kinematic range ($1 \lt Q^2 \lt 7$ GeV$^2$, $0.1 \lt x_B \lt 0.7$). For this purpose, A Low Energy Recoil Tracker (ALERT) is being built to work in conjunction with the CLAS12 spectrometer to measure recoil fragments with momenta as low as 70 MeV/c. The ALERT detector consists of a low gain stereo drift chamber and a scintillator array allowing reliable separation of $^{4}{He}$, $^{3}{He}$, $^{3}{H}$, deuterons, and protons. Implementation of new artificial intelligence (AI) track reconstruction methods are proven to be beneficial for experiments conducted at high instantaneous luminosities in which the number of background hits is significantly increased. The improved tracking accuracy and overall particle identification that can be achieved with modern machine-learning techniques are crucial for these experiments. In this talk, a brief highlight of the ALERT program will be given along with the status of the AI-assisted tracking under development.

This work is supported in part by the US DOE contract #DE-FG02-07ER41528.

Speaker: Mikhail Yurov (Mississippi State University)

2023_04_ghp_m_yurov.pdf

3:20 PM (tbd)

2:00 PM → 3:40 PM Parallel Session: Lattice Studies in QCD, Chair: Martha Constantinou

2:00 PM A continuum Schwinger method to study the pion's structure at future electron ion colliders

The formalism of Dyson-Schwinger equations is a powerful tool to study correlation functions in quantum field theory, but has also proved to yield an outstanding framework for the evaluation of hadron properties. Starting from state of the art continuum Schwinger calculations of pion's parton distribution function, we describe its extension to off-forward hadron kinematics, yielding the pion's generalized parton distribution. From that point on, we evaluate the amplitude for deeply virtual Compton scattering (DVCS) in the kinematic regime covered at the foreseen Electron-Ion Collider. Predictions for the event-rates and beam spin asymmetries to be observed are presented, revealing the dominance of gluon content within the pion in driving its response to DVCS at future electron-ion collider energies.

Speaker: Jorge Segovia (Pablo de Olavide U., Seville)

Slides_GHP-APS_JS.pdf

2:20 PM Moments of nucleon generalized parton distributions from the leading-twist expansion of the quasi-GPD matrix element

We present a lattice QCD determination of the nucleon generalized parton distributions (GPDs) from an analysis of the quasi-GPD matrix element within the leading-twist framework. We preform our study on a Nf=2+1+1 twisted mass fermions ensemble with a clover improvement. The faster and more effective lattice QCD calculations of GPDs using the asymmetric frames was applied so that we can achieve multiple momentum transfers $t$ with reduced computational cost. The quasi-GPD matrix elements are renormalized using ratio scheme and analyzed using the leading-twist Mellin operator product expansion (OPE) at the next-to-leading order. We find a robust result for the first non-vanishing Mellin moments <x> and <x^2> as a function of $t$.

Speaker: Xiang Gao (Argonne National Lab)

GHP_0412_Gao.pdf

2:40 PM Transverse momentum-dependent parton distributions for longitudinally polarized nucleons from Lattice QCD

Previous Lattice QCD calculations of nucleon transverse momentum-dependent parton distributions (TMDs) focused on the case of transversely polarized nucleons, and thus did not encompass two leading-twist TMDs associated with longitudinal polarization, namely, the helicity TMD $g_1 $ and the worm-gear TMD $h_{1L}^{\perp } $ corresponding to transversely polarized quarks in a longitudinally polarized nucleon. Based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections, TMD observables characterizing the aforementioned two TMDs are evaluated, utilizing a RBC/UKQCD domain wall fermion ensemble at the physical pion mass. The results suggest that $h_{1L}^{\perp } $ is significantly suppressed in magnitude compared to its counterpart, the worm-gear TMD $g_{1T} $, deviating from the generic prediction of quark models, and thus indicating the influence of strong gluonic dynamical effects.

Speaker: Michael Engelhardt (NMSU)

talk_ghp.pdf

3:00 PM Isoscalar Parton Distribution with Disconnected Diagrams

In this talk, I will present results of the isoscalar quark parton distribution function (PDF) with disconnected diagrams. PDFs measure the distributions of quarks within hadrons and are used as a theoretical input to interpret results from collider experiments probing the Standard Model. These PDFs are determined by using Lattice Quantum Chromodynamics with the pseudo-PDF approach. Disconnected diagrams particularly have issues with signal-to-noise, we employ Multi-Grid deflation and a new coloring scheme for the probing technique that is designed to work well for non-zero displacements in the quark and anti-quark fields.

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

ChamnessGHP2023.pdf

3:20 PM GUMP program for GPD global analysis

Generalized Parton Distributions (GPDs) have been one of the most important tools to access the nucleon 3D structure including its mass, angular momentum and mechanical properties. However, the extraction of GPDs has been challenging due to its high-dimension nature. Recent progress in lattice QCD have brought in many insights into the studies of GPDs. In this talk I will introduce the GPDs through Universal Moment Parameterization (GUMP) program which aims to combine these lattice inputs together with various experimental measurements to obtain the state-of-the-art GPDs from global analysis.

Speaker: Yuxun Guo (University of Maryland, College Park)

GUMP_GHP_2023 Animated.pdf

GUMP_GHP_2023.pdf

3:40 PM → 4:00 PM Break

4:00 PM → 5:40 PM Parallel Session: Collinear PDFs, Chair: Jing Wang

4:00 PM Gluon TMD studies with heavy quarkonium states

Although significant results were obtained concerning quark transverse-momentum dependent distribution functions (TMD PDFs), the deep knowledge on their formal properties being surrounded by a rich and wealthy phenomenology, the gluon-TMD field represents an almost uncharted territory. After a brief introduction of gluon TMD PDFs and their connection with spin studies, we report progresses done via model-dependent calculations of T-even and T-odd functions at leading twist. We then review the potential of new-generation colliding machines to catch the inner dynamics of gluons inside protons via (un)polarized TMD studies in heavy-quarkonium emissions.

Speaker: Francesco Giovanni Celiberto (ECT*/FBK Trento & INFN-TIFPA)

talk_GHP_2023_Celiberto_gluon_TMDs_onium.pdf

4:20 PM Simultaneous Global Analysis of Di-Hadron Fragmentation Functions and Transversity PDFs

We propose a new definition of unintegrated di-hadron fragmentation functions (DiFFs) which is compatible with the probability interpretation of collinear DiFFs and derive the leading-order evolution equations for these DiFFs. With these new definitions, we perform the first simultaneous extraction of DiFFs and transversity PDFs using data from semi-inclusive annihilation (SIA) in electron-positron collisions, semi-inclusive DIS, and proton-proton collisions. In particular, we include new SIA data from Belle that provides, for the first time, experimental constraints on the unpolarized DiFFs, as well as proton-proton data from STAR at center of mass energy 500 GeV. We present results for the transversity PDFs and tensor charge and explore the impact of theoretical constraints such as the Soffer bound and lattice computations of the tensor charge.

Speaker: Christopher Cocuzza (Temple University)

GHP2023.pdf

4:40 PM Basics of factorization in a scalar Yukawa field theory

The factorization theorems of quantum chromodynamics (QCD) apply equally well to most simple
quantum field theories that require renormalization but where direct calculations are much more
straightforward. Working with these simpler theories is convenient for stress-testing the limits of the
factorization program and for examining general properties of the parton density functions (pdfs) or
other correlation functions that might be necessary for a factorized description of a process. With
this view in mind, we review the steps of factorization in a real scalar Yukawa field theory for both
deep inelastic scattering (DIS) and semi-inclusive deep inelastic scattering (SIDIS) cross sections.
In the case of SIDIS, we illustrate how to separate the small transverse momentum region, where
transverse momentum dependent (TMD) pdfs are needed, from a purely collinear large transverse
momentum region, and we examine the influence of subleading power corrections. We also review
the steps for formulating TMD factorization in transverse coordinate space, and we study the
effect of transforming to the well-known b∗-scheme. Within the Yukawa theory, we investigate the
consequences of switching to a generalized parton model (GPM) approach, and compare with a fully
factorized approach. Our results highlight the need to address similar or analogous issues in QCD.

Speaker: Fatma Aslan (JLab/UConn)

F_Aslan_GHP23.pdf

5:00 PM Leading Power Accuracy in Lattice Calculations of Parton Distributions

In lattice-QCD calculations of parton distribution functions (PDFs) via large-momentum effective theory, the leading power correction appears as ${\cal O}(\Lambda_{\rm QCD}/P^z)$ in matching to the quasi distributions due to linearly-divergent self-energy in quasi-PDF operators. For lattice data with hadron momentum $P^z$ of a few GeV, this correction is important for accurate predictions of the effective theory. We show how to attain the leading power accuracy by fixing the scheme of non-perturbative mass renormalization in the quasi-PDFs consistent with the summation/regularization method of the infrared-renormalon series in the matching coefficients. A demonstrative example on the pion PDF data at $P^z = 1.9$ GeV is shown to improve the theoretical error in matching by a factor of $3$ in the region $x= 0.2\sim 0.5$.

Speaker: Rui Zhang (University of Maryland, College Park)

GHP_Rui.pdf

5:20 PM Complementarity in Joint Lattice-Experiment Analysis of Parton Distributions

Parton Distributions encode the universal way in which partons, ie quarks and gluons, distribute themselves within a hadron and are necessary for interpreting certain hadronic cross sections with Standard Model particles. By inverting the relationship between experimental cross sections and theoretical partonic cross sections, phenomenologists determine these parton distributions. Over the past decade, Lattice QCD calculations have related matrix elements to those distributions in a similar way. In this talk, I will present the recent work between the HadStruc and JAM collaborations at analyzing experimental cross-sections and lattice results simultaneously. Even a few lattice data can have a substantial impact on the precision of the pion PDFs. We also study the impact of lattice data on a recent controversy in the sign of the nucleon's gluon helicity distribution.

Speaker: Dr Joseph Karpie (Jefferson Lab)

Karpie_ghp_2023.pdf

4:00 PM → 5:40 PM Parallel Session: Exotics, Dynamics, Scalars, Chair: Eric Swanson

4:00 PM The Search for Hybrid Mesons at GlueX

The quark model predicts a hierarchy of mesons with certain allowed $J^{PC}$, but experimental evidence has been found for several states with $J^{PC}$ that are forbidden for a pure quark anti-quark state. In the light quark sector, the most well studied of these states is the $\pi_1(1600)$. This state has several properties consistent with lattice QCD predictions for a light hybrid meson, a meson with an excited gluonic field. The GlueX experiment has collected high statistics photoproduction data, which will be used to study the properties of the $\pi_1(1600)$. This talk will summarize the current analysis efforts and future prospects for studying the $\pi_1(1600)$ at GlueX.

Speaker: William Imoehl (Carnegie Mellon University)

GHP_DRAFT.pdf

4:20 PM Three-body dynamics of resonances from lattice QCD

A pilot calculation to extract the $a_1(1260)$ resonance from lattice QCD data is presented. Complementing calculations in the infinite volume help understand the properties of this three-body resonance, like pole position and branching ratios. The presented work is based on arXiv:2107.03973 and arXiv:2112.03355.

Speaker: Michael Doring (George Washington U and Jefferson Lab)

GHP_2023_Michael_Doering.pdf

4:40 PM Analytic continuation of the relativistic three-particle scattering amplitudes

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Many hadronic resonances, including the most intriguing ones (Roper, $\pi_1(1600)$, or $T_{cc}^+(3872)$), decay into three or more particles. To determine their masses and widths from Lattice QCD, one has to supply existing three-body formalisms with amplitude analysis techniques. In particular, one has to analytically continue reaction amplitudes extracted from the finite-volume calculation to the complex energy plane.

In the talk, I will present a study of the analytic continuation of relativistic three-particle integral equations for a system composed of three identical scalar bosons. As an illustration, I will consider a scattering process in which a bound state forms in the two-body sub-channel. After discussing the analytic properties of the scattering amplitude, I will show the solution procedure involving analytic continuation via the integration contour deformation and present the resulting three-body scattering amplitudes for complex energies in the physical and unphysical Riemann sheets. In particular, I will present evidence for three-particle bound states in the system under study that agrees with previous work utilizing relativistic finite-volume formalism.

Finally, I will also comment on the obtained numerical evidence of the breakdown of the two-body finite-volume formalism in the vicinity of left-hand cuts.

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Speaker: Sebastian Dawid (University of Washington)

SDawid_GHP2023.key

SDawid_GHP2023.pdf

5:00 PM Extracting the Sigma resonance from first-principles QCD

We determine, from Lattice QCD, the elastic $\pi \pi$ scattering amplitudes in the three possible isospin channels and the $\sigma$ resonance. We extract its lineshape for several different quark masses corresponding with the state transitioning from bound to resonance. The extraction of the $\sigma$ pole position becomes very challenging when the state is unstable. We perform the first full dispersive analysis over lattice QCD data to reduce the systematic uncertainties and extract the resonance with high accuracy and improved precision.

Speaker: Arkaitz Rodas (Jefferson Lab)

AR_GHP_2023.pdf

5:20 PM Towards accessing $\gamma^{\star} \gamma^{\star} \to \pi\pi$ from lattice QCD

Two-pion production from photon-photon fusion plays a key role in many physical processes, such as studying the substructure of the scalar mesons or constraining the hadronic contribution of the muon’s anomalous magnetic moment. A new theoretical framework has been developed which maps the $\gamma^{\star} \gamma^{\star} \to \pi\pi$ amplitude to finite-volume matrix elements that can be computed using Lattice QCD. In this talk, I will outline how this new formalism can be implemented for the case of scalar resonances, where glueball candidates are expected to populate the spectrum. By computing the appropriate matrix elements and necessary $\pi\pi$ scattering processes, these scalar resonance to two-photon couplings can be determined from first-principles QCD.

Speaker: Andrew Jackura (University of California, Berkeley)

GHP_2023_Jackura.pdf

4:00 PM → 5:40 PM Parallel Session: Nuclear phase diagram from Heavy Ions to Neutron Stars, Chair: Ramona Vogt

4:00 PM Baryon Stopping and Associated Production of Mesons in Au+Au Collisions at $\sqrt{s_{NN}}=3.0$ GeV at STAR

Charged particles in heavy-ion collisions have various production mechanisms, such as thermal and associated production, and the importance of each changes with the collision energy. Studying the yields of charged particles provides a way to investigate the properties of the produced QCD matter in heavy-ion collisions and the various production mechanisms. The RHIC Beam Energy Scan (BES) programs cover a wide range of energies, including the transition from a hadronic dominated medium to a partonic dominated medium. The recently completed BES-II program was designed to improve and extend upon the results from the BES-I program. Of particular interest is the high baryon density region which is accessible through the STAR fixed-target program, extending the energy reach from $\sqrt{s_{NN}}=7.7$ GeV down to $\sqrt{s_{NN}}=3.0$ GeV. This presentation reports on measurements of charged particle production in Au+Au collisions at the lowest end of the STAR fixed-target program: $\sqrt{s_{NN}}=3.0$ GeV. Measurements of the proton stopping will be presented in addition to measurements of the production of $K^{+}$ in association with the $\Lambda$ baryon. Invariant yields and rapidity density distributions of $\pi^{\pm}$, $K^{\pm}$, and $p$ will also be presented, which will help to unravel the relative importance of the different particle production mechanisms.

Speaker: Benjamin Kimelman (Vanderbilt University)

Kimelman_GHP2023.pdf

4:20 PM Study the effects of pre-hydrodynamic flow in heavy-ion collisions at the RHIC Beam Energy Scan program

The (3+1)D hydrodynamics + hadronic transport hybrid models are effective quantitative tools to study the dynamics of relativistic heavy-ion collisions and to extract the transport properties of the Quark-Gluon Plasma. For collisions with $\sqrt{s_\mathrm{NN}} \sim O(10)$~GeV, the pre-equilibrium evolution before hydrodynamics plays an important role because it can reach up to 30\% of the total collision lifetime. In this work, we parameterize the transverse pre-hydrodynamic flow with a blast-wave-like profile, $v_\perp(r_\perp) = \tanh(\alpha r_\perp)$, for individual hot spots. We will show that the flow profiles with certain values of $\alpha$ can reproduce those generated from the free-streaming model. We further perform a systematic study on how the pre-hydrodynamic flow affects final-state observables in heavy-ion collisions at the RHIC Beam Energy Scan program. We will show its sensitivity to the anisotropic flow ratio $v_3/v_2$ and the HBT radii.

Speaker: Mashhood Munir (Wayne State University)

The effects of pre-hydrodynamic flow.pdf

4:40 PM Proton number cumulants and correlation functions at RHIC-BES from hydrodynamics

I will present the behavior of proton number cumulants and correlation functions in heavy-ion collisions based on relativistic hydrodynamics, incorporating essential non-critical contributions such as the exact conservation of multiple conserved charges and baryon excluded volume. I will also discuss the resulting constraints on the possible location of the QCD critical point coming from RHIC-BES I data, as well as future perspectives with BES II.

Speaker: Volodymyr Vovchenko (University of Houston)

Vovchenko-GHP-2023.pdf

5:00 PM Study net proton fluctuations with (3+1)D hybrid simulations and machine learning

Numerical simulations of the (3+1)D hydrodynamic + hadronic transport hybrid model provide quantitative descriptions of the dynamics of relativistic heavy-ion collisions from a few GeV to a few TeV [1]. The net proton cumulants in the final state encode important information about the QCD phase structure. However, studying high-order cumulants of net proton fluctuations require more than millions of simulation events, which poses a big computational challenge. In this work, we develop a neural network to mimic the net baryon charge evolution in the full (3+1)D hybrid model. The trained neural network enables us to efficiently compute the net proton cumulants. Based on the trained neural network, we study the net proton cumulants from fluctuations of initial-state baryon stopping modeled by the 3D Monte-Carlo Glauber model at the RHIC Beam Energy Scan energies.

[1] C. Shen and B. Schenke, “Longitudinal dynamics and particle production in relativistic nuclear collisions,” Phys. Rev. C 105, no.6, 064905 (2022)

Speaker: Brandon Boudreaux (Wayne State University)

BOUDREAUX-Talk.pdf

5:20 PM Nuclear phase diagram: from heavy ions to neutron stars

Nuclear matter populates a very important part of the high-energy or QCD phase diagram, where fundamental information is currently provided by theory, laboratory experiments, and astrophysics. How to translate between results obtained from different environments that produce different conditions is one of the most important open questions in nuclear physics today. I address how differences in isospin, strangeness, and magnetic field strength can modify the structure and position of coexistence lines in the phase diagram.

Speaker: Veronica Dexheimer (Kent State University)

Dexheimer.pdf

4:00 PM → 5:40 PM Parallel Session: Ultra Peripheral Collisions, Chair: Vicki Greene

4:00 PM ALICE results and future prospects on UPCs

In this talk, we will present recent results from the ALICE Collaboration on ultra-peripheral heavy-ion collisions and discuss future projects.

Speaker: Daniel Tapia Takaki (University of Kansas)

DTT - APS GHP April 2023 v4.pdf

4:20 PM CGC for Ultra-Peripheral Pb+Pb Collisions at the Large Hadron Collider: a more realistic calculation

We provide the first calculation of two-gluon production at mid-rapidity in ultra-peripheral collisions in the Color Glass Condensate framework. To estimate systematic uncertainty associated with poor understanding of the wave function of the nearly real photon, we consider two diametrically different models: the dilute quark-antiquark dipole approximation and a
vector meson, in which color charge density is approximated by McLerran-Venugopalan model. In the experimentally relevant range, the target nucleus can be faithfully approximated by a highly saturated state. This simplification enables us to perform efficient numerical simulations and extract the two-gluon correlation functions and the associated azimuthal harmonics.

Speaker: Haowu Duan (North Carolina State University)

UPC_GHP_2023.pdf

4:40 PM Tracking the baryon quantum number with heavy-ion collisions

The baryon number is a conserved quantity in quantum chromodynamics (QCD), which is typically divided equally among the valence quarks in baryonic matter. There is an alternative theory suggesting that the baryon number is carried by a non-perturbative, Y-shaped topology of gluons called the baryon junction, which connects all three valence quarks. Neither theory has been experimentally verified yet. Preliminary results from semi-inclusive photonuclear collisions identified using $\rm{Au}\rm{+}\rm{Au}$ collisions at $\sqrt{s_{NN}} = 54.4~\rm{GeV}$ have shown significant baryon stopping (an excess of baryons compared to anti-baryons) and rapidity asymmetry at low transverse momentum, which is consistent with the baryon junction picture.

We now present additional studies to differentiate between the two pictures. Our finding, based on data from isobar collisions (${}^{96}_{44}\rm{Ru} + {}^{96}_{44}\rm{Ru}$ and ${}^{96}_{40}\rm{Zr} + {}^{96}_{40}\rm{Zr}$) at $\sqrt{s_{NN}} = 200~\rm{GeV}$ recorded by the STAR experiment, shows that at mid-rapidity ($|y| < 0.5$), the ratio of baryon stopping ($B_\text{net}$) to net charge difference between the two systems ($\Delta C_\text{net}$) is roughy twice the ratio of mass number to atomic number differences (i.e. $96/4$) in central events.
%The uncertainty of $\Delta C_\text{net}$ is reduced in isobar systems by expressing the difference of net charge between the two systems as the sum of products of particle yields and double ratios. No tracking efficiency correction is needed on double ratios, which eliminates the associated uncertainty.
$\Delta C_\text{net}$ is measured with great precision thanks to the almost identical running conditions for the isobar collisions, resulting in a cancellation of the systematic uncertainties. If both charge and baryon numbers are carried by the valence quarks, $B_\text{net}/\Delta C_\text{net}$ should be close to $96/4$, which is supported by calculations from Ultra-relativistic Quantum Molecular Dynamics model that does not include baryon junction. The observed enhancement in baryon stopping favors the baryon junction hypothesis, as the baryon junction would have different interaction cross section and distribution function compared to quarks. Additionally, a centrality dependence of $B_\text{net}/\Delta C_\text{net}$ is observed, the shape of which is consistent with the effect of different neutron skins in the two isobar species.

Speaker: Chun Yuen Tsang (Kent State University)

GHP_2023_7.pdf

5:00 PM (tbd)

5:20 PM (tbd)

6:00 PM → 8:40 PM GHP Business meeting

6:00 PM Overview and Welcome

Speaker: Julia Velkovska (Vanderbilt University)

GHP23BusinessMeeting_Velkovska.pdf

6:10 PM Report from DOE

Speaker: Tim Hallman (DOE)

Hallman_DNP_GHP_04122023.pdf

Hallman_DNP_GHP_04122023.pptx

6:30 PM Report from NSF

Speaker: Allena Opper (National Science Foundation)

April-APS-opper.v1-GHP.pdf

6:50 PM Report from Jefferson Lab

Speaker: Patrizia ROSSI (JEFFERSON LAB)

GHP_business meeting_JLab.pdf

7:05 PM Report from BNL

Speaker: Haiyan Gao (BNL and Duke University)

BNL-GHP-April2023-HGao.pdf

7:20 PM Report from EIC Project

Speaker: Jim Yeck

APS Meeting April 2023_sm.pdf

7:35 PM Treasurer Report

Speaker: James Dunlop (BNL)

JCD-Apr2023-Business.pdf

7:45 PM Fellowships and Prizes

Speaker: Will Brooks (Universidad Técnica Federico Santa María)

Brooks_business_meeting.pdf

7:55 PM GHP engagement

Speaker: Dave Gaskell

GHP_engagement.pdf

8:00 PM Discussion

Thursday, April 13

8:30 AM → 10:30 AM Plenary Session: 3, Chair: Will Brooks

8:30 AM Probing ultra-dense gluonic matter via UPCs at CMS

Gluons are found to become increasingly dominant constituents of nuclear matter when being probed at higher energies or smaller Bjorken-$x$ values. This has led to the question of the ultimate fate of nuclear gluonic structure and its interaction with external probes at extreme density regimes. In ultrarelativistic heavy ion collisions, the electromagnetic fields surrounding an ion, quantized as linearly polarized quasi-real photons, can interact with the ion at a distance greater than the sum of their radii, known as ultraperipheral collisions (UPCs). In UPCs, the coherent heavy flavor vector meson via photonuclear interactions is of particular interest, as its cross section can directly probe the nuclear gluon density function at leading order. In this talk, we will present recent results on coherent vector meson photoproduction in 2018 UPC PbPb collisions at 5.02 TeV from the CMS experiment including a new measurement of coherent J/$\psi$ photoproduction with the forward neutron tagging technique. We will discuss the related physics implications, as well as exciting opportunities in future LHC heavy ion runs.

Speaker: Dr Zaochen Ye (Rice University)

VM-UPCs-CMS-ZaochenYe-GHP2023.pdf

9:00 AM Jet Substructure and its utility in small and large systems

Jets are algorithmic realizations of the fragmentation and hadronization patterns of high energy quarks and gluons liberated in relativistic hadron collisions. The last few years have witnessed an explosion of interest in jet substructure from both experimentalists and theorists. These substructure observables are derived from exploiting the information present in the clustering algorithms. Since jets are inherently multi-scale objects, the include both perturbative and non-perturbative physics. In this talk I will start with a pedagogical introduction to jet substructure and discuss the evolution of the observables from the last decade to the current state-of-the-art measurements. We then look forward to data from the upcoming RHIC runs, preview the planned substructure measurements in both small systems (proton-proton and proton-Gold collisions) and heavy ion (Gold-Gold) collisions and provide an pathway towards discovery physics outlined at the EIC.

Speaker: Raghav Kunnawalkam Elayavalli (Vanderbilt University)

jetss_utility_small_large_raghav_ghp2023.pdf

9:30 AM Heavy flavor, quarkonia, and exotic hadrons in hot QCD

Quantum Chromodynamics (QCD) predicts a deconfined state of quarks and gluons: Quark Gluon Plasma (QGP). Studying the transport and medium properties of QGP will greatly deepen our understanding of the strong interaction. Heavy quarks created in the collisions are golden probes of the medium and provide unique insights into in-medium energy loss, diffusion coefficient, hadronization mechanism and the temperature of QGP. Moreover, the fate of exotic hadrons in heavy-ion collisions opens new opportunities to revealing their nature that remains unknown since two decades ago. In this talk, I will discuss the fruitful experimental studies of heavy-flavors, quarkonia and exotic hadrons in heavy-ion collisions and the perspectives for the future experiments.

Speaker: Jing Wang (MIT)

20230412_GHPworkshop_HF_JingWang_v4.pdf

10:00 AM Extreme matter and neutron star collisions

Since the first detection of gravitational waves from the coalescence of neutron stars in 2017, many new discoveries and constraints have been placed on matter at large baryon densities. The study of dense matter has also been facilitied by heavy-ion collsions at low beam energies. Heavy-ion collisions experiments from RHIC at Brookhaven National Laboratory have ran the Beam Energy Scan and Fixed Target program that reach similar densities to those in neutron stars but are at finite temperatures. Synergies between extreme matter in the laboratory and in the coalescence of neutron stars are only beginning to be explored. In this talk I will discuss connections that exist at the level of the equation of state and out-of-equilibrium properties and how these connections will be strengthened as new data comes from future facilities and upgraded gravitational wave detectors.

Speaker: Jacquelyn Noronha-Hostler (University of Illinois Urbana Champaign)

GHP_2023.key

GHP_2023.pdf

10:30 AM → 11:00 AM Break

11:00 AM → 12:30 PM Plenary Session: 4, Chair: David Gaskell

11:00 AM Bridge Simulation to Experiments: Unsupervised Unpaired Data Translation between Domains

Many large-scale physics experiments, such as ATLAS at the Large Hadron Collider, Deep Underground Neutrino Experiment and sPHENIX at the Realistic Heavy Ion Collider, rely on accurate simulations to inform data analysis and derive scientific results. Their inevitable inaccuracies may be detected and corrected using heuristics in a conventional analysis workflow.
However, residual errors introduce intractable bias when the simulations are used to train Artificial Intelligence/Machine Learning (AI/ML) methodologies and those trained models are used to infer data from real detectors. Our goal is to develop a physics-informed ML framework that can bridge the gap between simulations and experiments. We realize this goal by applying Generative Adversarial Networks to transform data between different domains to augment existing simulations and to extract subtle differences that may eventually help improve our knowledge on the underlying physics process. Our initial effort demonstrated the feasibility of this approach using a Vision Transformer augmented U-Net on toy data from Liquid Argon Time Projection Chamber simulations. In this talk, we present the latest results on this work, including investigations for the best neural network architectures, the efforts on optimization and stabilization of the performance and initial results on benchmark datasets in the computer vision field as well as on realistic data from large scale physics experiments.

Speaker: Yihui Ren (BNL)

YRen_2023_GHP_workshop_v1.pdf

YRen_2023_GHP_workshop_v2.pdf

11:30 AM Short Range Correlations in Nuclei

Overview

Speaker: Axel Schmidt (George Washington University)

schmidt_ghp23.pdf

12:00 PM Probing Hadronization Dynamics with SIDIS Production off Nuclei

The combination of hard probes and pioneering processes such as semi-inclusive deep inelastic scattering (SIDIS) on atomic nuclei is a powerful tool to access medium modifications of their underlying structure, explore the hadronization mechanisms, and study QCD confinement dynamics in the cold nuclear medium. Indeed, the study of the hadronization process in such a clean environment is effective in probing the fragmentation mechanisms related to color propagation and hadron formation and thus its associated time-distance scales. In this talk, I will highlight recent hadronization results from Jefferson Lab with a focus on the first-ever SIDIS study of lambda hyperon in the current and target fragmentation regions. The new lambda results have the potential to improve our understanding of quark-diquark correlations and open a new era of studies of nucleon and light hyperon structure.

Speaker: Lamiaa El Fassi (Mississippi State University)

HadronGHP-Apr23.pdf

12:30 PM → 2:00 PM Lunch

2:00 PM → 3:40 PM Parallel Session: Generalized Parton Distributions, Chair: Alexei Prokudin

2:00 PM Proton GPDs from lattice QCD with novel methods

We present lattice QCD results on the unpolarized and helicity GPDs for the proton using a novel method that decomposes the matrix elements into Lorentz-invariant amplitudes. This work is an extension of the proof-of-concept calculation presented in Phys.Rev.D 106 (2022) 11, 114512, which demonstrated that more optimized calculations of GPDs are applicable to any frame, with freedom in the transferred momentum distribution. The numerical calculations presented in this talk use one ensemble of Nf=2+1+1 twisted mass fermions with a clover improvement. The value of the light-quark masses leads to a pion mass of about 260 MeV. Concentrating on the proton and zero skewness, we extract the invariant amplitudes from matrix element calculations in both the symmetric and asymmetric frame and obtain results for the twist-2 light-cone GPDs for unpolarized quarks, 𝐻 and 𝐸, as well as for the chiral-even polarized \tilde{H}.

Speaker: Joshua Miller (Temple University)

GHP_2023_Miller_Final.pdf

2:20 PM Shedding light on shadow generalized parton distributions (GPDs)

The feasibility of extracting generalized parton distributions (GPDs) unambiguously from deeply-virtual Compton scattering data (DVCS) has recently been questioned due to the existence of an infinite set of so-called ``shadow GPDs'' (SGPDs). These SGPDs are process-dependent, and manifest as multiple solutions---at a fixed $Q^2$---to the inverse problem in DVCS that needs to be solved to obtain the GPDs. That is, SGPDs characterize different possible solutions to this inverse problem that each give identical contributions to observables for a given $Q^2$. We revisit the extent that scale evolution can provide constraints on SGPDs. This is possible because the known classes of SGPDs begin to contribute to observables after evolution to a different $Q^2$ and can no longer be considered SGPDs. Therefore, these SGPDs can be constrained by data that has a finite $Q^2$ range. We separately conduct this analysis for the $H$ and $E$ GPDs, and discuss the impact that the SGPDs could have on the determination of the spin sum, pressure and sheer force distributions, and tomography. Our key finding is that scale evolution, coupled with data over a wide range of $\xi$ and $Q^2$, can constrain the known classes of SGPDs and make possible the extraction of GPDs from DVCS data over a limited range in the GPD variables.

Speaker: Eric Moffat (Argonne National Lab)

GHP_Moffat_4_13_23.pdf

2:40 PM Phenomenology of proton and deuteron deeply virtual exclusive scattering

One of the best ways to understand the spin structure of the proton is through Generalized parton distributions (GPDs) which are in principle accessible in exclusive deeply virtual photon electroproduction processes. However, in order to extract these GPDs, a proper understanding of the phase structure of the cross section is vital. In particular, the phase structure plays a key role in the extraction of GPDs closely related to the proton’s orbital angular momentum. As a step towards understanding this phase structure, we study deeply virtual photon electroproduction from a spin ½ quark target. We provide the general expression for the various contributions to the cross section, namely: the deeply virtual Compton scattering process, the Bethe-Heitler process, and their interference. All of these are described within a helicity amplitude based framework that is relativistically covariant, making it readily applicable to both laboratory and collider kinematic settings. We will discuss calculations of observables (cross sections and spin asymmetries) for the proton and deuterin targets, providing details on the electric charge, quadrupole, magnetic, and axial vector properties.

Speaker: Joshua Beethoven Bautista (University of Virginia)

GHP 2023-Bautista.pdf

3:00 PM Evolution and the modelling of GPDs

Evolution equations which control the scale dependence of generalized parton distributions (GPDs) are a crucial tool to extract accurately these objects from experimental data. They determine the propagation of uncertainty in the deconvolution problem of factorized observables, and offer a great opportunity to model GPDs in the small Bjorken-x limit. We use the recent momentum-space evolution code APFEL++ interfaced in the PARTONS framework to present results on the uncertainty of the extraction of GPDs, graviational form factors and the extrapolation of GPDs to vanishing skewness, an important aspect of the 3D-tomography program.

Speaker: Hervé Dutrieux (College of William & Mary)

Presentation_2023_04_13__GHP_.pdf

3:20 PM (tbd)

2:00 PM → 3:40 PM Parallel Session: J/Psi at Threshold, Chair: Patrizia Rossi

2:00 PM Near-threshold quarkonium production and gravitational form factors

I will talk about recent developments in the theory of gravitational form factors and discuss how they can be accessed in near-threshold quarkonium photo- and electro-production.

Speaker: Yoshitaka Hatta (Brookhaven National Laboratory)

Hatta.pdf

2:20 PM Threshold charmonium photoproduction with GlueX

The charmonium photoproduction near threshold can be used to study important aspects of the gluon structure of the proton, such as the gluon Generalized Parton Distribution (GPD), the gravitational form factors, the mass radius of the proton, and the anomalous contribution to the proton mass. However, such an ambitious program requires precise measurements over the full kinematic range to validate the theoretical assumptions that relate the experimental results to the above quantities. We report the total and differential cross sections for $J/\psi$ photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold of $8.2$ GeV up to $11.44$ GeV and over the full kinematic range of momentum transfer squared, $t$. Such measurements enable more general conclusions about the reaction mechanism when compared to a wide range of theoretical predictions including GPD calculations and models with open-charm intermediate states. Photoproduction of higher-mass charmonium states near threshold will be discussed, as well.

Speaker: Lubomir Pentchev (Jefferson Lab)

LPentchev_Jpsi_GHP2023.pdf

2:40 PM Recent results from near-threshold J/Ψ photoproduction measurement from Hall-C J/Ψ-007 experiment

Measurement of near threshold quarkonia photoproduction cross section provides a unique tool to probe gluonic structure inside the nucleon, hence allowing extraction of gluonic form factors and mass radii. 𝐽/Ψ-007 experiment (E12-16-007) was conducted at Hall-C of the Thomas Jefferson National Accelerator Facility to measure near threshold 2-D differential 𝐽/Ψ photoproduction cross section as a function of photon energy 𝐸𝛾 and Mandelstam variable 𝑡 (momentum transfer from initial photon to the produced 𝐽/Ψ). The experiment utilized a high intensity real photon beam produced by incidence of a 10.6 GeV incident electron beam on a copper radiator situated upstream of a hydrogen target. The produced e−e+ (𝜇−𝜇+) pair from decay of 𝐽/Ψ was detected using two arm spectrometers in Hall C: the HMS and the SHMS. The scanned photon energy range 𝐸𝛾 and momentum transfer |𝑡|, are between 9.1 GeV and 10.6 GeV and up to 4.5 GeV2, respectively. Recent results from analysis of the measured 2-D 𝐽/Ψ photoproduction cross section (e−e+ channel) will be presented. In addition,
preliminary results from analysis of muon channel will be also be shown.

Speaker: Shivangi Prasad (Argonne National Laboratory)

SPrasad_GHP_2023.pdf

3:00 PM J/ψ near threshold in holographic QCD: A and D gravitational form factors

The diffractive photoproduction of J/Ψ on a nucleon is mostly due to gluonic exchanges at all s. In holographic QCD (large number of colors and strong  ′t Hooft coupling), these exchanges are captured by gravitons near threshold, and their reggeized form (Pomeron) asymptotically. We revisit our holographic analysis of the A and D gravitational form factors in light of the new lattice data, and use them to refine our predictions for the photoproduction of J/Ψ near threshold, and the comparison to the GlueX data. We use these results to estimate the scalar and mass radii of the nucleon, and describe the gravitational pressure and shear across a nucleon. We also discuss the recent extraction of gluonic form factors of proton, by J/Ψ-007 collaboration at JLab, using our holographic scattering amplitude for near threshold J/Ψ photoproduction.

Speaker: Kiminad Mamo (ANL)

Exclusive charmonium production and gluonic structure-Mamo.pdf

3:20 PM Charmonium photo production

I Will discuss JPAC analysis of the recent results on J/psi photo production and prospects for charm studies at the next generation photo/lepton facilities.

Speaker: Adam Szczepaniak (IU/JLab)

GHP-Aprli-2023-Szczepaniak.pdf

2:00 PM → 3:40 PM Parallel Session: Meson Structure, Chair: Dave Gaskell

2:00 PM Measurements of Light Meson Structure via Tagged Deep Inelastic Scattering

This talk will discuss upcoming tagged deep inelastic scattering (TDIS) measurements at Jefferson Lab, which will directly probe the elusive mesonic content of the nucleon. The TDIS experiment will measure low momentum recoiling (and spectator) hadrons in coincidence with deep inelastically scattered electrons from hydrogen (and deuterium) targets. The recently commissioned Super Bigbite Spectrometer, a large acceptance detector package, will be used to detect the electrons. For hadron detection, a novel multiple time projection chamber (mTPC) is being developed. This innovative mTPC will be a high-rate capable device optimized for measuring protons and pions spanning momenta of 60-400MeV/c. Through use of the mTPC, a tagging technique will enhance deep inelastic scattering from partons in the meson cloud and provide access to the pion and kaon structure functions. Existing world data on light meson structure is extremely sparse and the TDIS measurements will be crucial for shedding light on topics such as emergent hadron mass. An overview of the measurements, setup, current status, projected results and future extensions of the measurements will be given.

Speaker: Rachel Montgomery

Montgomery_GHP_Apr2023.pdf

2:20 PM Pion and kaon form factors from lattice QCD

We present a calculation of the scalar, vector, and tensor form factors for the pion and kaon in lattice QCD. We use two ensembles of maximally twisted mass fermions with clover improvement with two degenerate light, a strange, and a charm quark $(N_f=2+1+1)$ at lattice spacings of 0.093 fm and 0.081 fm. The pion mass of the ensembles is about 250-260 MeV. The excited-states effects are studied by analyzing six values of the source-sink time separation for the rest frame (1.12 − 2.23 fm) and for four values for the boosted frame (1.12 − 1.67 fm). The lattice data are renormalized non-perturbatively and the results for the scheme- and scale-dependent scalar and tensor form factors are presented in the MS scheme at a scale of 2 GeV. We apply different parametrizations to describe $q^2$-dependence of the form factors to extract the scalar, vector and tensor radii, as well as the tensor anomalous magnetic moment. We compare the pion and kaon form factors to study SU(3) flavor symmetry breaking effects. By combining the data for the vector and tensor form factors, we also obtain the lowest moment of the densities of transversely polarized quarks in the impact parameter space. We give an estimate for the average transverse shift in the y direction for polarized quarks in the x direction. We compare all these results across both ensembles for analysis of discretization effects.

Speaker: Joseph Delmar (Temple University)

Delmar_GHP_2023.pdf

2:40 PM The Non-Perturbative Structure of Pion

Several works have attempted to understand the pion valence partonic distribution function (PDF), both experimentally and theoretically. Questions remain, especially for the high x region. Using the recently developed Residual Field Model, we calculate the pion valence PDF in the range of 0.1<x<1. Within the model, the pion transitions into valence and residual subsystems described by their respective light-front wave functions. Within the valence subsystem, there are two mechanisms that describe the valence quarks of the pion at different x: the soft contribution and the hard quark-quark short-range component. The parameters of soft LF wave functions are fixed by fitting the calculation to the well-established properties of phenomenological pion PDFs. One such property is the peaking structure of x-weighted valence quark distribution in the pion which occurs at x ~ 0.4, where we expect the soft contribution to dominate. We explore different analytic forms for the valence quark-antiquark light front wave function in which the short distance is described by Coulomb-type interaction while the long-distance part is by a harmonic oscillator-like system which accounts for the confinement. With the parameters of soft quark-anti quark and residual wave functions fixed, we calculate the high x -component by considering the mechanism of hard gluon exchange between valence quarks. This allows us to make predictions on the form of the high-x pion PDF distribution that can be verified in the future measurements of pion PDF at a high x limit.

Speaker: Joseph Maerovitz (Florida International University)

The Non-Perturbative Structure of Pion2_Joseph_Maerovitz.pdf

3:00 PM Update On Meson Structure Studies at Jefferson Lab Hall C

The development of the GPD formalism in the last 25 years has been a groundbreaking advance in our understanding of the structure of the nucleon. Unifying the concepts of parton distributions and of hadronic form factors, GPDs contain a wealth of new information about how quarks and gluons make up hadrons. For example, GPDs correlate different parton configurations within the hadron at the quantum mechanical level. A recent theorem allows the reaction amplitude to be factorized into a hard part, representing the interaction of the incident virtual photon probe with the parton, and a soft part, containing the GPD and, representing the response of the nucleon to this interaction. Importantly this factorization relies on several assumptions that may not be true at low four momentum transfer squared (Q^2) for meson production. The main assumption is that the cross section will depend on Q^-6. This presentation will give the projected results of the recently completed Pion-LT experiment from Jefferson Lab Hall C. These results will test the validity of GPD factorization in the range of 1.45 GeV^2 <= Q^2 <= 8.5 GeV^2, and will have implications for several GPD extraction experiments currently planned.

Speaker: nathan heinrich (University of Regina)

GHP_GPDFactorization_2023.pdf

3:20 PM Extracting the Pion Distribution Amplitude from Lattice QCD through Pseudo-Distributions

The light-cone distribution amplitude (DA) encodes non-perturbative information of the wave function of fast moving hadrons. In particular, cross sections for high energy exclusive processes factorize into the pion DA, directly probing the internal structure of the pion, as well as providing constraints on proton structure via Deeply Virtual Meson Production. In this talk, I will present the extraction of the pion DA from three Nf=2 ensembles with lattice spacings in the range 0.0483-0.0749 fm at a pion mass of ~440 MeV. The pseudo-distribution formalism is employed to extract the DA from the renormalized lattice matrix elements.

Speaker: Daniel Kovner (William & Mary)

ghp_daniel_kovner_pion_da.pdf

2:00 PM → 3:40 PM Parallel Session: Short Range Correlations, Chair: Axel Schmidt

2:00 PM New results from A(e,e’p) measurement on Short-range correlations in Neutron-rich nuclei

Short-Range Correlations (SRC): pairs of strongly interacting nucleons whose distance is comparable to their radii. Due to their overlapping quark distributions and strong interaction, SRC pairs serve as a bridge between nucleon interaction and partonic structure, with important consequences for strong-interaction physics, hadronic structure, and other studies. Some of the most intriguing SRCs results come from asymmetric nuclei measurement, specifically that in neutron-rich nuclei. The recent result suggested that the inclusion of proton-neutron SRCs inverts the energy sharing between the Fermions in neutron-rich nuclei, giving the minority larger average kinetic energy. In this talk, first I will give a quick summary of where we stand on SRCs study in neutron-rich nuclei, second I will present the preliminary from new A(e,e’p) measurement on Ca isotope and Iron from Hall C, Jlab. The results from this experiment will provide insight into SRCs in neutron-rich nuclei, in particular on the separation of the contribution of proton and neutron to SRC

Speaker: Dien Nguyen (Jefferson Lab)

GHP_Dien_2023_updated.pdf

2:20 PM Recent Jefferson Lab Measurement on Inclusive Scattering from Nuclei at x$>$1

In the Jefferson Lab experiment, E12-06-105 performed in Hall C, we measured the inclusive scattering from a series of light to heavy nuclei at $x > 1$ in the quasielastic and deeply inelastic regimes. The measurement of quasielastic scattering from extremely high-momentum nucleons at moderate $Q^2$ but very large $x$ is a great tool to gain insight on the short-range structure and nucleon–nucleon correlations in nuclei. On the other hand, the measurement at high $Q^2$ and moderately high $x$ is dominated by the deep inelastic scattering (DIS) from the $x \ge 1$ part of the nuclear parton distributions. The latter can be used to probe the distribution of super fast quarks (SFQs) which is sensitive to short-range structure in nuclei. The E12-06-105 experiment ran concurrently with E12-10-008 (EMC Effect) experiment in Hall C at Jefferson Lab and used 10.5 GeV electron beam incident on several cryogenic and solid targets. I will present an overview of the E12-06-105 experiment and online/preliminary results.

Speaker: Burcu Duran (University of Tennessee)

BD-GHP-23.pdf

2:40 PM Probing nuclear short-range correlations with real photons at Jefferson Lab

Probing nuclear short-range correlations with real photons at Jefferson Lab

Speaker: Tim Kolar

TimKolar-GHP2023.pdf

3:00 PM Nuclear short-range correlations with the generalized contact formalism

The generalized contact formalism (GCF) is a useful model for analyzing the properties and implications of nuclear short-range correlations (SRCs). Based on an asymptotic factorization of the wave function when two-particles are found close to each other, the GCF was used to study two-body densities and momentum distributions, electron scattering reactions, and more, resulting in a consistent and comprehensive picture regarding the effects of SRC pairs. In this talk, I will present an overview of the GCF and then recent results regarding the description of three-nucleon SRCs, subleading corrections to the short-distance wave-function factorization, and calculations of neutrinoless double beta decay matrix elements in which SRC effects are accounted for.

LA-UR-23-21999

Speaker: Ronen Weiss (Los Alamos National Lab)

GHP_2023_20min.pdf

3:20 PM QCD in Nuclei: Hidden Color Singlets and Diquark Phenomenology

Recent proposals for hadronic physics contributions to nuclear structure and dynamics in the form of diquark-based short-range correlations (SRC) and hidden color states in nuclear wavefunctions will be discussed. While hidden color states have a 40-plus year history as rigorous predictions of the SU(3) basis of QCD, future experimental developments promise unprecedented access to their study. Hidden color states are typically built upon diquark bonds and this connection will be made explicit. Long standing mysteries such as the EMC effect and the fundamental QCD basis of SRC pairs in nuclei may have solutions based on the new diquark dynamics described herein.

Speaker: Jennifer Rittenhouse West (Berkeley Lab)

jrw-MINNEAPOLIS-GHP2023-updated.pdf

3:40 PM → 4:00 PM Break

4:00 PM → 5:40 PM Parallel Session: EMC Effect, Chair: Nadia Fomin

4:00 PM First Measurement of the Flavor Dependence of Nuclear PDF Modification Using Parity-Violating Deep Inelastic Scattering

The EMC effect has been known for almost 40 years but it still needs to be fully understood theoretically and there are essentially no reliable experimental constraints on its flavor dependence. In order to better understand the EMC effect, We propose a clean and precise measurement of the flavor dependence of the EMC effect using parity-violating deep inelastic scattering on a 48Ca target. This measurement will provide an extremely sensitive test for flavor dependence in modifying nuclear pdfs for neutron-rich nuclei. A measurement of the flavor dependence will provide new and vital information and help to explain nucleon modification at the quark level. In addition to helping understand the origin of the EMC effect, a flavor-dependent nuclear pdf modification could significantly impact a range of processes, including neutrino-nucleus scattering, nuclear Drell-Yan processes, or e-A observables at the Electron-Ion Collider.
The parity-violating asymmetry APV from 48Ca using an 11 GeV beam at 80 μA will be measured using the SoLID detector in its PVDIS configuration. In 68 days of data taking, we will reach 0.7-1.3 % statistical precision for 0.2<x<0.7 with 0.6-0.7 % systematic uncertainties. The goal is to make the first measurement of the flavor dependence of the EMC effect. The precision of the measurement will allow for quantification of the flavor-dependent effects, greatly improving our ability to differentiate between models of the EMC effect. The proposal has received conditional approval from JLab PAC50 in 2022.

Speaker: Rakitha Beminiwattha (Louisiana Tech University)

Beminiwattha_PVEMC_Talk_APS_Hadron_2023.pdf

4:20 PM Isovector EMC Effect from JAM Global QCD Analysis with MARATHON Data

Understanding the nuclear effect is critical to reduce the Parton Distribution Functions (PDFs) uncertainties at large x. Traditionally, the nuclear effect is assumed to be isoscalar. A new study within the JAM global framework by including the MARATHON He3/H3 data implements an isospin dependent off-shell correction. The results suggest an enhanced nuclear effect on the d-quark PDF in the bound proton. This indicates an isovector effect in nuclear structure functions, and demonstrate the power of combining the MARATHON He3/H3 data with a global QCD analysis to provide simultaneous information on PDFs and nuclear effects in A ≤ 3 nuclei.

Speaker: Hanjie Liu (Brookhaven National Laboratory)

GHP2023_Hanjie_LIU.pdf

4:40 PM Understanding the EMC effect with tagged DIS measurements

Understanding the modification of quarks in nucleons within nuclei (EMC effect) is a longstanding open question in nuclear physics. Recent experimental results from electron scattering at Jefferson Lab strengthen the correlation between the EMC effect and short- range correlated pairs (SRC) of nucleons in nuclei. That means that the EMC effect is probably driven by the high-momentum highly-virtual nucleons of the SRC pairs. This connection can be tested experimentally by measuring electron deep inelastic scattering from a nucleon and detecting its correlated SRC partner nucleon (tagging). This allows us to measure the quark modification of high-momentum nucleons.

Two tagged experiments on deuterium are underway at Jefferson Lab of which one already took data and the other will take data next year.
In my talk, I will present the current knowledge of the EMC-SRC correlation, and present preliminary results from the tagged experiment on deuterium at Jefferson Lab's experimental HallB where the modification of protons were measured by tagging the recoiling neutrons.

Speaker: Florian Hauenstein (Jefferson Lab)

Hauenstein_ghp2023.pdf

5:00 PM EMC effect measurements at 11GeV

I will report on the Jefferson Lab(JLab) Hall C experiment E12-10-008 (EMC effect) that is currently running and will finish data taking by mid February. Multiple cryogenic and solid targets were used to measure inclusive electron scattering using a 10.5 GeV beam from the Continuous Electron Beam Accelerator Facility at JLab. In this experiment, for a series of light to heavy nuclei, we measured inclusive electron scattering cross section ratios at x<1, where the EMC effect dominates, and at x>1 where contributions from nucleon-nucleon short-range correlations are relevant. The analysis of this data will further elucidate the connection between the nuclear quark distributions and the high-density configurations in nuclei and also shed more light on the nuclear dependence of the EMC effect. The EMC effect data for Boron-10 and -11 from a running period in 2018 has also been analyzed. I will present an outline of the related physics, an overview of how the experiment was conducted, and online analysis results in addition to the EMC effect results for Boron targets.

Speaker: Abhyuday Sharda (University of Tennessee, Knoxville)

Abhyuday Sharda GHP.pdf

5:20 PM Medium-modified spin structure functions in the EMC and anti-shadowing regions

The exploration of medium modification of unpolarized structure functions in nuclei has been underway for several decades. The theoretical descriptions of this effect, known as the “EMC effect”, are numerous and there is currently no universal community consensus about its cause, although connections to short-range correlations do appear to be plausible. In this talk I will discuss something new, the very first investigation into the modification of polarized structure functions in the nuclear medium. I will discuss an approved Jefferson Lab experiment to measure bound proton spin structure functions in the 7Li nucleus with an 11 GeV electron beam, and also the possibilities to extend this measurement to an upgraded Jefferson Lab with a 22 GeV electron beam.

Speaker: Will Brooks (Universidad Técnica Federico Santa María)

Brooks-Antishadowing_GHP.pdf

4:00 PM → 5:40 PM Parallel Session: J/Psi and Hadron Properties, Chair: Patrizia Rossi

4:00 PM Observation of new structures in the J/psiJ/psi mass spectrum in pp collisions at 13 TeV

A search is reported for low-mass structures in the J/ψJ/ψ mass spectrum produced by proton-proton collisions at s√=13TeV. The data sample corresponds to an integrated luminosity of 135 fb−1 collected by the CMS experiment at the LHC. Modelling signals with relativistic Breit-Wigner shapes, and under the assumption of the absence of interference between signal components, and between signal and background, three structures are identified. Two structures are observed with local significances well above 5 standard deviations at masses of 6927±9(stat)±5(syst)MeV and 6552±10(stat)±12(syst)MeV. The first one is consistent with the previously observed X(6900). Evidence for a third structure is found at a mass of 7287±19(stat)±5(syst)MeV with a local significance of 4.1 standard deviations.

Speaker: Kai Yi (Nanjing Normal university)

10thGHP2023v1.pdf

4:20 PM Polarization measurement of coherent J/psi photoproduction with the ALICE experiment

In this talk, we will present the measurement of the polarization of coherent J/psi photoproduction in ultra-peripheral lead-lead collisions using Run 2 data from the ALICE experiment. We will also discuss future prospects for angular correlation studies.

Speaker: Amrit Gautam (University of Kansas)

Amrit_4_13_2023.pdf

4:40 PM Status of the MUon proton Scattering Experiment (MUSE)

The MUon proton Scattering Experiment (MUSE) was built to address the proton radius puzzle by simultaneously measuring the proton radius from both $e^\pm p$ and $\mu^\pm p$ elastic scattering in a momentum transfer range sensitive to the radius extraction. The experiment is carried out at the Paul Scherrer Institute (PSI) and uses a mixed e, $\mu$, and $\pi$ beam, alternating between positive and negative polarities, in the PiM1 secondary beam line. This, in combination with a large-acceptance, non-magnetic detector system allows the MUSE apparatus to measure the elastic $e^\pm p$ and $\mu^\pm p$ scattering cross sections and cross section ratios in 0.002 $< $Q$^2 <$ 0.08 (GeV/c)$^2$ and 0.26 $< \epsilon <$ 0.94 regime over a wide momentum range (115 to 210 MeV/c). Each of the four sets of data will allow the extraction of the proton charge radius. In combination, the data test possible differences between the electron and muon interactions and two-photon exchange effects. MUSE has commissioned its apparatus to the level needed for the measurements and began data collection in 2021. In this talk, the current status of the experiment will be discussed.

Speaker: Ievgen Lavrukhin (University of Michigan)

MUSE_GHP_2023_Ievgen_Lavrukhin.pdf

5:00 PM Potential Model Calculations of Proton Mass Radius with Constrained Charge Radius

The effective radius of the proton varies depending on the force through which it interacts with its surroundings. While the charge radius, relevant to electromagnetic interactions, is known to within a few hundredths of a fermi, the mass radius, relevant to gravitational interactions, is still heavily disputed. Experimental measurements (e.g. from GlueX), lattice QCD calculations and various theoretical models pin the value to between 0.55 and 0.7 fm. We instead calculate the mass radius using a potential model of the strong force interaction between quarks. We adapt the Coulomb-plus-linear, or Cornell, potential for the proton in two ways. In the naive method, chromoelectric flux tubes extend pairwise between each pair of quarks and the potential energy only depends on the relative distances between them. In the second method, we modify the confining part of the potential so that the flux tubes join together at a central junction. Additionally, we consider a quark-diquark configuration. In all cases, we mandate that the proton wave functions reproduce the known charge radius. In addition to calculating its mass radius, this technique allows us to map the spatial energy distribution of the proton and discern which contributions to the total energy are dominant at different mass radii. We find that the charge radius strongly constrains the quarks’ dynamical contributions which would give a mass radius in the relatively high range. We also find that the mass radius is sensitive to how the vacuum contributions such as the constituent quark mass are treated, which could lead to a considerably smaller mass radius.

Speaker: Daniel Gallimore (Indiana University Bloomington)

Mass Radius Presentation.pdf

Mass Radius Presentation.pptx

5:20 PM (tbd)

4:00 PM → 5:40 PM Parallel Session: Probes of QGP, Chair: Raghav Kunawalkam Elayavalli

4:00 PM Identifying Quenching Effect in Heavy-ion Collisions with Machine Learning

Measurements of jet substructure in ultra-relativistic heavy ion collisions suggest that the jet showering process is modified by the interaction with quark gluon plasma. Modifications of the hard substructure of jets can be explored with modern data-driven techniques. In this study, we use a machine learning approach to the identify quenched jets. Jet showering processes, with and without the quenching effect, are simulated with the JEWEL model. Sequential substructure variables are extracted from the jet clustering history following an angular-ordered sequence, and are used in the training of a neural network built on top of a long short-term memory network. We measure the jet shape and jet fragmentation function from the neural network outputs. The results support that the machine learning approach successfully identifies the quenching effect in the presence of the large uncorrelated background of soft particles created in heavy ion collisions.

Speaker: Yilun Wu (Vanderbilt University)

MachineLearningJetQuenching_YilunWu_GHP.pdf

4:20 PM Understanding the production of heavy flavor exotics in heavy ion collisions

For heavy ion collisions in the TeV beam energy region, the large number of initial hard scatterings create a richly "doped" hot quark-gluon plasma containing many charm quarks/anti-quarks. This provides a uniquely "charming" environment for the massive production of heavy flavor exotic hadrons, with the notable examples of X(3872) and Tcc states, and possibly helps solve puzzles about their intrinsic structures, as demonstrated by recent theoretical studies. Furthermore, fresh experimental data have started to arrive from LHCb and CMS and indicate nontrivial partonic medium effects on their production, whereas a clear understanding of relevant mechanisms is lacking. This talk will report two exciting theoretical results along this direction. First, we demonstrate how heavy ion measurements could help decipher the exotic structure between two popular model configurations: a loose hadronic molecule or a compact tetraquark. It turns out the two different structures have rather different sensitivity to the fireball volume in heavy ion collisions. By scanning centrality and thus systematically tuning the fireball volume, our dynamical simulations have indeed found about 2-order-of-magnitude difference in the X(3872) yield and a markedly different centrality dependence between hadronic molecules and compact tetraquarks. This offers a novel approach for using fireball size as a “yardstick” to calibrate the size of X(3872) and thus distinguishing the two scenarios. More recently such study has also been extended to the newly observed doubly-charmed exotic states, with similar findings. Second, we propose a new mechanism for medium-assisted production of X(3872) and use state-of-the-art hydrodynamic simulations to show how this can help quantitatively explain the latest LHCb and CMS data for its yield dependence on multiplicities from pp to pA and AA collisions. [Refs: PRL126(2021)1,012301; PRD104(2021)11,L111502; arXiv:2302.03828] [Supported by NSF Grant No. PHY-2209183]

Speaker: JINFENG LIAO (INDIANA UNIVERSITY BLOOMINGTON)

LIAO_GHP2023.pdf

4:40 PM Φ Meson Production at Forward Rapidity in Au + Au Collisions at √SNN = 200 GeV

A major objective in the field of high-energy nuclear physics is to
quantify and characterize the quark-gluon plasma formed in relativistic
heavy-ion collisions. The ϕ meson is an excellent probe for studying
this hot and dense state of nuclear matter because of its very short
lifetime. The ϕ->µ+µ- decay channel is particularly interesting because
the decay muons do not interact with its surrounding matter. Since ϕ
meson is composed of a strange and anti-strange quark, its nuclear
modification in heavy-ion collisions may provide an insight into
strangeness enhancement in-medium. The PHENIX experiment at RHIC has
measured ϕ meson with its muon spectrometers installed at forward region
(1.2 < |y| < 2.2) in a variety of p(d)+A collision systems at different
energies. Similar measurement in Au + Au collisions may provide useful
information about the hot nuclear matter (HNM) created in these events.
In this talk, we will present the analysis report of ϕ meson production
at forward rapidity in Au + Au collisions at √SNN = 200 GeV.

Speaker: Uttam Acharya (Georgia State University)

Acharya_Uttam_GHP2023_v2.pdf

5:00 PM The evolution of jets and high-$p_T$ probes in small collision systems using a multi-stage approach.

Investigating the modifications of jets and high-$p_T$ probes in small systems requires the integration of soft and hard physics. The recent advancements in the JETSCAPE framework have led to the development of an event generator that considers the correlations between soft and hard partons to study jet observables in small systems. This hybrid approach separates the multi-scale physics of the collision into several stages. First, hard scatterings are calculated using binary collision positions from the Glauber geometry, then they are propagated backward in space-time using an initial-state shower to determine the energies and momenta of the initiating partons. The energies and momenta are then subtracted from the incoming nucleons for soft-particle production, which is modeled using the 3D-Glauber + hydrodynamics + hadronic transport framework. The framework takes into account the non-trivial correlations between jet and soft particle production in small systems and is calibrated with measured event activity distributions in p+p collisions at 5.02 TeV. We present the resulting hadrons' $p_T$-spectra and compare the model with different observables at the LHC.

Speaker: ismail soudi (Wayne State University)

Soudi-GHP2023.pdf

5:20 PM The sPHENIX experiment at RHIC

sPHENIX will start data taking in Spring 2023 at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Built around the excellent BaBar superconducting solenoid, the central detector consists of a silicon pixel vertexer adapted from the ALICE ITS design, a silicon strip detector with single event timing resolution, a compact TPC, novel EM calorimetry, and two layers of hadronic calorimetry. The plan is to use the combination of electromagnetic calorimetry, hermetic hadronic calorimetry, precision tracking, and the ability to record data at high rates without trigger bias to make precision measurements of Heavy Flavor, Upsilon, and jets to probe the Quark Gluon Plasma (QGP) formed in heavy ion collisions. These measurements will have a kinematic reach that not only overlaps those performed at the LHC, but extends them into a new, low-pT regime.
The sPHENIX physics program, its potential impact, and the recent detector development will be discussed in this talk.

Speaker: Dr Weihu Ma (Fudan University)

The sPHENIX experiment at RHIC.pdf

4:00 PM → 5:40 PM Parallel Session: Transverse Momentum Dependent Distributions, Chair: Alexei Prokudin

4:00 PM Tomography of pions and protons via transverse momentum dependent distributions

We perform the first simultaneous extraction of parton collinear and transverse degrees of freedom from low-energy fixed-target Drell-Yan data in order to compare the transverse momentum dependent (TMD) parton distribution functions (PDFs) of the pion and proton. We demonstrate that the transverse separation of the quark field encoded in TMDs of the pion is more than $\sim 5 \sigma$ smaller than that of the proton. Additionally, we find the transverse separation of the quark field decreases as its longitudinal momentum fraction decreases. In studying the nuclear modification of TMDs, we find clear evidence for a transverse EMC effect. In this talk, we discuss the methodology and various results, which call for a deeper examination of tomography in a variety of strongly interacting quark-gluon systems.

Speaker: Patrick Barry (Jefferson Lab)

Barry_GHP.pdf

4:20 PM Rapidity-only TMD factorization at one loop

Typically, a production of a particle with a small transverse momentum in hadron-hadron collisions is described
by CSS-based TMD factorization at moderate Bjorken $x_B\sim 1$ and by $k_T$-factorization at small $x_B$.
A uniform description valid for all $x_B$ is provided by rapidity-only TMD factorization developed in a series
of recent papers at the tree level. In this paper the rapidity-only TMD factorization for particle production iby
gluon fusion is extended to the one-loop level.

Speaker: Ian Balitsky (JLab/ODU)

Balitsky_GHP2023.pdf

4:40 PM Mapping Nucleon and Meson Parton Distributions with Lattice QCD

There has been rapid development in direct calculations of Bjorken-x dependent structure using large‐momentum effective theory (LaMET) and similar frameworks. In this talk, I will highlight selected results in the quark and gluon parton distribution functions of the pion, kaon, and nucleon and our attempts toward precision lattice PDF calculations using multiple lattice spacings. I also discuss some recent efforts toward calculating the pion and nucleon generalized parton distributions (GPDs) directly at physical pion mass.

Speaker: Huey-Wen Lin (Michigan State University)

Lin_H-W_GHP23.v2.pdf

5:00 PM Transverse-momentum-dependent factorization at next-to-leading power

We present our results for TMD factorization at sub-leading power beyond, and leading order in the strong coupling, focusing on the matching of the large and small transverse momentum contribution in semi-inclusive deep inelastic scattering processes (SIDIS and Drell Yan). We pay special attention to azimuthal modulations of polarized and unpolarized cross sections such as the Cahn effect. Our results have consequences for the studying the intrinsic transverse motion of quarks in the nucleon, the so called 3-D structure of the nucleon, beyond leading power ("twist"). Additionally, our study has far reaching consequences for applying universality of TMDs beyond leading power to future (and past) phenomenological studies.

Speaker: Leonard Gamberg (Penn State Berks)

Gamberg_GHP_23.pdf

5:20 PM Consistent large transverse momentum matching in TMDs with “Hadron Structure Oriented” approach

TMD observables are normally expressed in terms of their contributions coming from different regions in transverse momentum. The low transverse momentum is often ascribed to an intrinsic non perturbative property of the hadron, described by TMD factorization, while the large transverse momentum region can be computed using fixed order collinear perturbation theory. In the middle region, often called the matching region, the two techniques fail to provide a satisfactory interpolation resulting in significant tension. The standard techniques used in high-energy physics don't carry over for moderate hard scales spoiling the hadronic structure interpretation. A recent approach, designed to retain this physical interpretation, significantly alleviates this tension by providing phenomenologists and model builders with a very general tool to incorporate both perturbative and non perturbative contributions in the parametrization of TMD densities while guaranteeing the matching in the large transverse momentum region.

Speaker: Tommaso Rainaldi (Old Dominion University)

Rainaldi_GHP2023.pdf

6:00 PM → 10:00 PM Workshop Banquet

Friday, April 14

8:30 AM → 10:10 AM Parallel Session: Hadron Structure in QCD, Chair: Alexei Prokudin

8:30 AM Numerical Study of Twist-3 Longitudinal-Transverse Double-Spin Asymmetries: a Probe of Quark-Gluon-Quark Correlations in Hadrons

In this talk I will focus on the asymmetry ALT involving a longitudinally polarized electron or proton colliding with a transversely polarized proton, with a single pion, photon, or jet detected in the final state. We provide rigorous numerical predictions for Jefferson Lab, COMPASS, RHIC, and the future Electron-Ion Collider using recent extractions of the parton distribution functions (PDFs) and fragmentation functions (FFs) involved in calculating ALT. Uncertainty bands are generated through a bootstrapping method that randomly selects PDF/FF replicas with replacement until the computation converges. Through these predictions we hope to motivate future measurements that can help us gain more insight into the quark-gluon-quark interactions that occur inside of hadrons as well as dynamical quark mass generation in QCD.

Speaker: Brandon Bauer (Lebanon Valley College)

Bauer_GHP_Workshop_2023.pdf

8:50 AM Light front time and rest frame densities of hadrons

The Lorentz group of special relativity contains a Galilean subgroup, under which light front time is invariant. Using the light front time variable along with the ordinary three Cartesian spatial coordinates allows a fully relativistic spatial description of the internal structure of hadrons, specifically in the form of two-dimensional densities on the plane transverse to the observer's line of sight. This description is frame-independent, and thus provides a rest-frame picture of the hadron's charge, current, energy, momentum and stress distributions. The use of the light front time variable is physically interpreted as providing an alternative time synchronization convention, and the use of the usual three spatial coordinates allows all components of the electromagnetic four-current and the energy-momentum tensor to be given a clear physical interpretation. Densities of pions and nucleons are presented as examples.

Speaker: Adam Freese (University of Washington)

Freese_Slideshow.pdf

9:10 AM Confinement and Color Vortices in Chromostatics

ABSTRACT
This talk illustrates the chiral nature of the non-Abelian covariant derivative for SU(N) gauge groups. In the chromostatic limit, the interior volume of a hadron is filled by a single color-vortex. The Strong Conjecture for Color Confinement suggests that this volume is separated from an exterior volume by a domain wall of topological charge.

Speaker: Dennis Sivers (Portland Physics Insitute)

Sivers Minn2023 Apr13.pdf

9:30 AM Tsallis-MIT bag model pressure distribution and the physical meaning of the bag pressure

We consider the MIT bag model of hadrons with a Tsallis statistics. In the new framework we obtain a perspective in which the bag pressure can be dismissed by using the q parameter of the non-extensive statistics. This parameter effectively describes the interactions among the components in the hadron.

Speaker: Gerardo Herrera Corral (CINVESTAV)

Minneapolis-2023 - 3.pdf

Minneapolis-2023 - 3.pptx

9:50 AM The correlated spatial structure of the proton from double generalized parton distributions as a framework for dynamical imaging

Mapping the 3D structure of the proton in terms of its spinning quark and gluon constituents is one of the main goals of current hadronic physics investigations. Generalized parton distributions can provide part of the solution, connecting GPDs through Fourier transformation to the average spatial density of quarks and gluons with a given longitudinal momentum fraction, x. Notwithstanding the importance of this information, a fuller dynamical picture of the proton’s interior can be better captured by introducing two-particle spatial density distributions. The latter depend on the relative distance between partons and therefore provide a measure of the amount of correlations in the particles’ motion. Introducing double generalized parton distributions, we provide a description of the quark and gluon dynamics in terms of their spatial overlap probabilities. The latter allow us, for instance, to distinguish among configurations where the gluons either preferentially cluster around valence quarks, or are distributed in a diffused cloud configuration occupying the entire available space within the proton. In this talk I will focus on the gluon sector, presenting results using a spectator model based gluon GPD parametrization, and its extension to double GPDs.

Speaker: simonetta liuti (university of virginia)

liuti_panjsheeriGHP_23.pdf

8:30 AM → 10:10 AM Parallel Session: JLab 12 GeV and Future Intiatives, Chair: David Gaskell

8:30 AM Jefferson Lab Positron Program

The Jefferson Lab Polarized Electrons for Polarized Positrons (PEPPo) experiment demonstrated that it is possible to make polarized positrons with the polarized electron beam at CEBAF. Jefferson Lab is now looking to develop a dedicated positron source that will be able to feed the CEBAF accelerator with polarized positrons and deliver up to 11 GeV positrons to the experimental halls. I will present the plans for this new source as well as present an overview of the scientific program that is planned with this new source.

Speaker: Dr Douglas Higinbotham (Jefferson Lab)

01 Higinbotham-Positrons-GHP-2023.pdf

Higinbotham-Positrons-GHP-2023.pptx

8:50 AM Future Pion Structure Studies with JLab at 22 GeV and the EIC

One of the most puzzling aspects of the Standard Model is that the overwhelming majority of the mass of hadronic systems arises from massless and nearly massless objects. How this occurs is poorly understood, and remains a major open question of the standard model. From the little that we do understand, we know that mass generation is intricately connected to the internal structure of hadronic systems. Emergent Hadronic Mass is an elemental feature of the Standard Model. It is the origin of a running gluon mass, the source of Dynamical Chiral Symmetry Breaking, and very probably crucial to any explanation of confinement. Somewhat counter intuitively, it is one of the lightest hadronic objects, the charged pion, that may be able to fill in the missing piece of the puzzle. Advancing our understanding of the internal structure of the charged pion is crucial if we are to begin to untangle how this structure emerges from the dynamical nature of the interactions that govern it.

Fortuitously, in the coming decade we will see the construction of the only new accelerator facility scheduled to be built anywhere in the world, the Electron-Ion Collider (EIC). An upgrade of the electron beam energy at the Thomas Jefferson National Accelerator Facility (JLab), to 22 GeV, is also expected within this time frame. Both facilities can be utilised to advance our understanding of pion structure. In this talk, I will outline the prospects for future studies of pion structure at an upgraded 22 GeV JLab and at the EIC. In particular, I will examine the opportunities for future measurements of the charged pion elastic electromagnetic form factor, $F_{\pi}(Q^{2})$, deep into experimentally unexplored territory at both facilities, with a focus on the complementarity of these measurements.

Speaker: Dr Stephen Kay (University of Regina)

SJDK_GHP_2023.pdf

9:10 AM Gravitational form factors and mechanical properties of the proton

The mechanical properties of the proton, including angular momentum, mass, pressure, and shear forces, are encoded in the matrix element of the proton energy-momentum tensor and are expressed in the gravitational form factors (GFFs). Recent theoretical developments have shown that GFFs can be accessed in deeply virtual Compton scattering (DVCS) and in deeply virtual (vector) mesons production (DVMP). In DVCS, two photons couple to the proton and mimic the graviton-proton interaction, allowing to probe its mechanical properties. This new direction of research on nucleon structure has already enabled the determination of the pressure distribution inside the proton for the first time.
In this talk, we discuss the extraction of the shear forces and their spatial distribution and compare them to model predictions. We will also present the prospects for the future experimental program with the proposed Jefferson Lab energy upgrade and the US Electron-Ion Collider.

Speaker: Latifa Elouadrhiri (Jefferson Lab)

GHP-2023-Latifa.pdf

GHP-2023-Latifa.pptx

9:30 AM Experimental Studies of Evolution Properties of Structure Functions in Polarized SIDIS

The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations. Single and Dihadron semi-inclusive and hard exclusive production, both in current and target fragmentation regions, provide a variety of spin and azimuthal angle dependent observables, sensitive to the dynamics of quark-gluon interactions. Studies of spin-dependent structure functions, and underlying transverse momentum distributions of partons are currently driving the upgrades of several existing facilities, and the design and construction of new facilities worldwide.
In this talk, we present some ongoing and possible future studies of Q^2-dependences of structure functions in SIDIS, required for validation of existing theoretical description of SIDIS.

Speaker: Harut Avagyan (Jefferson Lab)

avakian-2023-APS-April14.pdf

9:50 AM Measurements of the Cosφ and Cos2φ Moments of the Unpolarized SIDIS π+ Cross-section at CLAS12

Semi-inclusive deep inelastic π+ electroproduction has been studied with the CLAS12 detector at Jefferson Laboratory. Data were taken by Run Group A at Hall B of the laboratory using a polarized 10.6 GeV electron beam, interacting with an unpolarized liquid hydrogen target. The collected statistics enable a high-precision study of the Cosφ and Cos2φ azimuthal moments of the unpolarized cross-sections. These azimuthal moments probe the Boer-Mulders function, which describes the net polarization of quarks inside an unpolarized proton, and the Cahn effect, which has a purely kinematic origin. The high statistics data will, for the first time, enable a multidimensional analysis of both moments over a large kinematic range of Q2, xB, z, and PT. We will present the status of this ongoing analysis, including the multidimensional unfolding procedures used for acceptance corrections.

Speaker: Richard Capobianco (University of Connecticut)

APS Richard Capobianco Measurements of the Cosφ and Cos2φ Moments of the Unpolarized SIDIS π+ Cross-section at CLAS12.pdf

8:30 AM → 10:10 AM Parallel Session: Light Meson Decays, Chair: Lubomir Pentchev

8:30 AM Precision tests of fundamental physics with light pseudoscalar mesons

Hadronic and radiative decays of light mesons decays offer a privileged environment to test QCD and search for physics beyond the Standard Model.
A new generation of precision experiments in hadron physics will soon offer new data that will have an impact on determinations of fundamental QCD parameters, such as the ratio of light quark masses or the $\eta$-$\eta^{\prime}$ mixing parameters, and provide important test of chiral symmetry breaking in QCD.
This new data will also provide sensitive probes to test potential new physics including searches for dark photons, light scalars and axion-like particles that will complement worldwide efforts to detect new light particles in the MeV-GeV mass range.
In this talk, I will give an update on the theoretical developments and discuss the experimental opportunities in this field.

Speaker: Sergi Gonzàlez-Solís (Los Alamos National Lab)

GHP23_Sergi.pdf

8:50 AM The physics program using the new JLab Eta(‘) Factory (JEF) in Hall D at Jefferson Lab.

The Jefferson Lab Eta Factory (JEF) is an experiment that is designed to run in Hall D at Jefferson Lab using the upgraded Gluonic eXcitations experiment (GlueX) facility to study the different decay modes of the eta meson (η). The present GlueX setup comprises a 2 Tesla solenoid magnet, a liquid hydrogen target, drift chambers used for tracking charged particles and an array of lead glass (PbO) blocks (the Forward Calorimeter) downstream of the magnet. For JEF, the PbO crystals closest to the beam line are being upgraded to Lead Tungstate (PbWO$_4$) crystals to improve photon detection efficiency. Measurement of η decay channels are used to determine the light-quark mass ratio via η→π$^+$π$^−$π$^0$ and η→3π$^0$ and allows access to higher-order terms in Chiral Perturbation Theory via η →π$^0$γγ. Additionally, η decays are used to constrain new charge conjugation violating - parity conserving reactions and to search for signatures of dark matter. In particular, η →π$^0$γγ is used to search for lepto-phobic dark vector (B) bosons in η→Bγ (Β→π$^0$γ) or dark scalar (S) bosons in η→π$^0$S (S→γγ). Studying the rare radiative decay channel η→π$^0$γγ required our replacing the 4×4×45 cm$^3$ PbO blocks in the inner region of FCAL with 2×2×20 cm$^3$ PbWO$_4$ crystals, which provide about a factor of two improvement in position and energy resolution

Speaker: Bill Briscoe (GWU)

Briscoe GHP23.pdf

9:10 AM Linking the 3P0 decay model to Landau gauge QCD

A quark-model treatment of hadron decays suggests that the creation of a constituent quark-antiquark pair occurs in a spin-triplet p-wave scalar configuration, 3P0 in spectroscopic Russell-Saunders notation. This chiral-symmetry breaking vertex has long been known to have to be nonperturbative since the fundamental underlying theory, chromodynamics, is to a good approximation chirally symmetric. Thus, such production vertex has to arise simultaneously to the constituent quark mass.
The last decade has brought detailed lattice data for the primitive vertices of QCD in Landau gauge. A practical use of this data has been to constrain Dyson-Schwinger parametrizations of the most elementary QCD Green's functions, that are now reasonably well known.
With this knowledge of the underlying theory in the infrared regime we attempt to connect the Landau gauge formalism and the constituent quark model to ascertain the relative size of the various possible structures in the quark-antiquark production vertex, including the postulated 3P0 quark-model piece.

Speaker: Felipe J. Llanes-Estrada (Univ. Complutense de Madrid)

Llanes-EstradaAPSApril143P0.pdf

9:30 AM A FAIR Phase-0 experiment to determine the $\pi^{0}$ electromagnetic transition form factor at MAMI

The PANDA FAIR Phase-0 experiment at the Mainz Microtron (MAMI) accelerator facility at Mainz in Germany is set to determine the double-virtual transition form factor (TFF) of the neutral pion via single-pion electroproduction. The determination of the electroproduction cross section on a highly charged target using low momenta transfers gives access to the so-called virtual Primakoff contribution, which is proportional to the $\pi^{0}$ TFF. As a result, the experiment can contribute to reducing the uncertainty in the calculation of the hadronic light-by-light (HLbL) scattering contributions to the hadronic corrections of the anomalous magnetic moment of the muon (g$_\mu$-2 puzzle). The detector system for the experiment is a modified version of the PANDA backward calorimeter (EMC), developed by the electromagnetic process group (EMP) at HI-Mainz. The detector will operate in forward direction within a strong electromagnetic environment at the A1 electron scattering facility. The talk gives an update on both simulations and test measurements. Furthermore, the current status of the experiment preparation will be presented.

Speaker: Oliver Noll (Helmholtz Institute Mainz)

noll_GHP2023.pdf

9:50 AM The REDTOP experiment: a $\eta$/$\eta'$ factory to explore dark matter and physics beyond the Standard Model

The $\eta$ and $\eta'$ mesons are almost unique in the particle universe because of their quantum numbers and the dynamics of their decay are strongly constrained. This effect increases the branching ratio of rare decays which can be studied to probe physics BSM. The integrated eta meson samples collected in earlier experiments have been about ~$10^9$ events, dominated by the WASA at Cosy experiment, limiting considerably the search for such rare decays. A new experiment, REDTOP, is being proposed, aiming at collecting more than $10^{14}$ eta/yr ($10^{12}$ eta'/yr) for studying of rare $\eta$ decays.
Such statistics are sufficient for investigating several symmetry violations, and for searches of new particles beyond the Standard Model.
Recent physics and detector studies indicate that REDTOP has excellent sensitivity to probe all four portals connecting the dark sector with the Standard Model. Furthermore, conservation laws and violation of discrete symmetries can be probed in several ways.
The physics program and the detector for REDTOP will be discussed during the presentation.

Speaker: Corrado Gatto (INFN & NIU)

GHP20230414_REDTOP.pdf

8:30 AM → 10:10 AM Parallel Session: Neutrino Hadron Interactions, Chair: Florian Hauenstein

8:30 AM An Introduction to Neutrino-Nucleus Interactions: A Generator Perspective

The forthcoming Deep Underground Neutrino Experiment aims to precisely measure all aspects of the neutrino mixing matrix across a wide range of neutrino energies. Thus, it is incumbent upon the community to deeply understand the scattering processes at play across DUNE's broadband beam, including quasielastic, meson-exchange current, resonance, and deep inelastic scattering. I'll briefly review the oscillatory physics targeted by DUNE's physics program, the physics of neutrino scattering, and how neutrino event generators such as GENIE are improving with DUNE in mind.

Speaker: Dr Joshua Barrow (MIT, TAU)

An Introduction to Neutrino-Nucleus Interactions: A Generator Perspective

Presentation-Hadron2023-JLBarrow.pdf

Presentation-Hadron2023-JLBarrow.pptx

8:50 AM Nuclear Effects in Neutrino Experiments

The ability of current and next generation accelerator based neutrino oscillation measurements to reach their desired sensitivity and provide new insight into the nature of our Universe, requires a high-level of understanding of the neutrino-nucleus interactions. These include precise estimation of the relevant cross sections and the reconstruction of the incident neutrino energy from the measured final state particles. Incomplete understanding of these interactions can skew the reconstructed neutrino spectrum and thereby bias the extraction of fundamental oscillation parameters and searches for new physics.
This talk will review the known nuclear effects relevant to neutrino oscillation experiments, the models describing them and methods to constrain those models' parameters.

Speaker: Adi Ashkenazi (Tel Aviv University)

230414_APS.pdf

9:10 AM The impact of neutrino-nucleus interactions on neutrino oscillation physics

Current and future accelerator-based neutrino facilities utilizing intense neutrino beams and advanced neutrino detectors are focused on precisely determining neutrino oscillation properties and signals of weakly interacting Beyond the Standard Model (BSM) physics. These are subtle effects, such as extracting the CP violation phase and disentangling parameter degeneracies between oscillation effects and BSM physics, and require an unprecedented level of precision in measurements. The potential of achieving discovery-level precision and fully exploring the physics capabilities of these experiments relies greatly on the precision with which the fundamental underlying neutrino-nucleus interaction processes are known. A non-trivial multi-scale, multi-process problem that lies in an uncharted territory that spans from low-energy nuclear physics to perturbative QCD with no known underlying unified physics. In this talk, I will discuss these challenges, provide some examples, and highlight some ongoing cross-community efforts tackling such a problem.

Speaker: Vishvas Pandey (Fermi National Accelerator Laboratory)

APS_GHP2023_VPandey.pdf

9:30 AM Measurement of axial vector form factor in antineutrino elastic scattering on free protons in the MINERvA experiment

Antineutrino scattering on free protons (or neutrino scattering off free neutrons) gives a unique measurement of neutron and proton structure and is a building block for predicting neutrino scattering on more complex nuclei. Previous measurements have had to rely on scattering neutrinos off deuterium and then correcting for poorly known nuclear effects, or by low intensity anti-neutrino beams. In this talk MINERvA will present the first high statistics cross section measurement of the charged current elastic process νμbar + p → μ+n using the plastic scintillator (CH). The carbon background is significantly reduced and constrained with minimal model dependency using the kinematics of the reconstructed neutrons. The result can be directly compared with lattice QCD computations, and to electron scattering off free protons.

Speaker: Tejin Cai (York University)

hydrogen_analysis_ghp2023_TejinCai.pdf

9:50 AM Compatibility of Neutrino DIS Data and Its Impact on Nuclear Parton Distribution Functions

In global analyses of nuclear parton distribution functions (nPDFs),
neutrino deep-inelastic scattering (DIS) data exhibit tensions with
the data from charged-lepton DIS. Using the nCTEQ framework, we
investigate the dependence of these tensions on the proton PDF baseline,
as well as the treatment of data correlation and normalization
uncertainties. We identify the experimental data and kinematic
regions that generate tensions, and also investigate a possibility
of managing the tensions by using uncorrelated systematic errors.
Understanding these tensions between the neutrino and charged-lepton
DIS data is essential not only for better flavor separation in
global analyses of nuclear and proton PDFs, but also for neutrino
physics and for searches for physics beyond the Standard Model.

Speaker: Fred Olness (SMU)

Olness_GHP.pdf

10:10 AM → 10:30 AM Break

10:30 AM → 12:10 PM Parallel Session: Computational and Quantum Computing,, Chair: Jacquelyn Noronha-Hostler

10:30 AM Spectroscopy of Ising Mesons on a Noisy Digital Quantum Simulator

Quantum simulation has the potential to be an indispensable technique in the investigation of non-perturbative phenomena in strongly interacting quantum field theories (QFTs). A central question in the current quantum era is: what non-perturbative QFT problems can be tackled with the Noisy Intermediate Scale Quantum (NISQ) machines? In this work, we provide an explicit example to this question by using a noisy IBM digital quantum simulator to compute the meson mass spectrum of 1+1D quantum Ising model with transverse and longitudinal fields. The latter is particularly appealing due to well-known analogs between confinement of domain-walls of the Ising model and that of quarks in t’Hooft’s 1+1D quantum chromodynamics. Going beyond existing works, using IBM’s digital quantum simulator, we compute the flow of the meson spectrum in the Ising QFT due to the variation of the transverse and longitudinal fields. Our results show that digital quantum simulation in the NISQ era can be a viable alternative to established numerical techniques such as density matrix renormalization group or the truncated conformal space methods for analyzing a large number of 1+1D QFTs.

Speaker: Ananda Roy (Rutgers University)

APS_Had_Phys_Workshop_AR.pdf

10:50 AM Quantum Computations for Field Theory Models in Hadron Physics and GPDs

Testing detailed predictions of QCD and searching for phenomena Beyond the Standard Model at the LHC and the EIC requires knowing spin dependent Parton Distribution Functions for quarks and gluons. For some observables Generalized or Transverse Momentum pdf’s are needed. Calculating these distributions from QCD, ab initio, is prohibitively resource intensive and depends on non-perturbative techniques. Simulation on a quantum computer of quantum field theories offers a new way to investigate properties of the fundamental constituents of matter. We develop quantum simulation algorithms based on the light-front formulation of relativistic field theories, beginning with Yukawa theories in 1+1D and 2+1D. We compute pdf’s and GPD’s for a model of pion-like mesons and quark-diquark baryons.

Speaker: Gary Goldstein (Tufts University)

GHP_goldstein_2023.pdf

11:10 AM Validation of the fragmentation reactions in GEANT4 tool against LISE++ for rare isotopes studies

Sokhna Bineta Lo Amar (1, 2)
Paul Gueye (2)
Oumar Ka (1)
(1) Cheikh Anta Diop University (UCAD), Dakar (Senegal)
(2) Facility For Rare Isotope Beams (FRIB), Michigan State University (USA)

Abstract. The study of unstable nuclei far from β-stability through fragmentation of heavy ion beams is one the most used approaches in low to intermediate energy nuclear physics to gain insights into their nuclear structure and the reaction mechanisms. The Facility for Rare Isotope Beam (FRIB) started its operation in May 2022 and is expected to produce upward of 1,000 predicted new isotopes for basic and applied nuclear science research. FRIB uses intensively the LISE++ and GEANT4 tools to model experimental setups. However, a comprehensive and systematic validation of these two codes against each other is lacking. This communication presents a comparative study of the distributions of the total cross section and production yield of rare isotopes using these two software tools.
140 MeV/u beam of 40Ar is used to interact with a 9Be target through the fragmentation process. Five GEANT4 physics models (Shielding, QGSP_BERT, QGSP_BIC, FTFP_BERT and QBBC) have been identified as adequate to describe these reactions. Their predictions are compared to those from LISE++ through its empirical tool (i.e., EPAX), which is a universal parameterized formula. The preliminary comparative results (Figure 1) show a good agreement of the fragmentation reaction between LISE++ and GEANT4, even if the pick-up process needs to be reviewed and improved in order to obtain a complete validation.
The identification of the discrepancies between the two codes, opens up the path to develop a systematic validation suite to benchmark each code for their future released versions and provide guidance of their physics usage to the low- and high-energy nuclear physics communities.

Keywords: Fragmentation reaction - GEANT4 - LISE++ - EPAX

Speaker: Dr Sokhna Bineta Lo Amar (FRIB/UCAD)

Amar_GHP2023.pdf

11:30 AM Towards Trapped-Ion Analog Simulation of Lattice Gauge Theories

Laser cooled atomic ions offer unprecedented control over both internal and external degrees of freedom at the single-particle level. They are considered among the foremost candidates for realizing quantum simulation and computation platforms that can outperform classical computers in specific tasks. Trapped ions can be used to simulate effective models of lattice gauge theories and to simulate their real-time dynamics. I will briefly cover recent advances in the use of trapped ions for digital quantum simulation of the Schwinger model [1,2]. I will then report on recent proposals and ongoing experimental efforts to simulate real-time dynamics of the Schwinger model in an analog fashion with either tailored two-body interactions [3] or higher-order spin-spin interactions [4]. Finally, I will discuss a hybrid digital-analog approach [5] to simulate the Yukawa and Schwinger models by a more efficient mapping of these theories onto the degrees of freedom of the trapped-ion simulator.

[1] E. Martinez et al., Nature 534, 516–519 (2016)
[2] N. Nguyen, et al., PRX Quantum 3, 020324 (2022)
[3] Z. Davoudi, et al., PRR 2, 023015 (2020)
[4] B. Andrade, et al., Quantum Sci. Technol., 7, 034001 (2022)
[5] Z. Davoudi, et al., PRR 3, 043072 (2021)

Speaker: Guido Pagano (Rice University)

09 GHPApril_Guido_Pagano_v1.pdf

GHPApril_Guido_Pagano_v1.pptx

11:50 AM The baryon anticorrelation problem may require modifying fragmentation in PYTHIA

Baryon anticorrelation measurements have disagreed with theory in the last few years: the number of experimental baryon pairs with small phase-space separation falls short from existing numerical Monte Carlo simulations.

We have computationally extracted baryon (anti)correlations from one of the best known Monte Carlo codes, PYTHIA, that produces them at the string-fragmentation level in the underlying Lund model; we then propose the simplest modifications that could lead to better agreement with data.

These are two ad-hoc changes in the fragmentation code, a "one-baryon" and "always-baryon" policies that qualitatively reproduce the experimental data behavior, i.e. anticorrelation, and suggest that lacking Pauli-principle induced corrections at the quark level could be the culprit behind the standing disagreement.

Speaker: Victor Gonzalez (Wayne State University)

Anticorrelations_20230414.pdf

10:30 AM → 12:10 PM Parallel Session: Electron Ion Collider, Chair: David Gaskell

10:30 AM Probing twist-2 GPDs through the exclusive photoproduction of a photon-meson pair at JLab and beyond

We employ QCD collinear factorisation to compute the exclusive photoproduction of a photon-meson pair with a large invariant mass at leading order in the strong coupling $\alpha_s$ and at the leading twist. The mesons we consider are either rho mesons [1] or charged pions [2,3]. In particular, having a transversely-polarised rho meson in the final state allows for chiral-odd GPDs to be probed at the leading twist, which are not well-known experimentally. This process thus represents one of the few promising channels to measure them. We compute the various cross-sections and the linear polarisation asymmetries wrt the incoming photon. We also perform the phase space integrals to obtain estimations of counting rates at various experiments, namely at JLab-12-GeV, COMPASS, future EIC and LHC in ultra-peripheral collisions [3]. In particular, the high centre-of-mass energies available in collider experiments enables the study of GPDs at small skewness, a region where they are not well-known. Finally, we discuss our recent progress in the computation of NLO corrections in $\alpha_s$, as well as the computation of having a neutral pion in the final state, which probes gluonic GPDs as well.

[1] R. Boussarie, B. Pire, L. Szymanowski, and S. Wallon, “Exclusive photoproduction of a γ ρ pair with a large invariant mass,” JHEP 02 (2017) 054, arXiv:1609.03830 [hep-ph]. [Erratum: JHEP 10, 029 (2018)]
[2] G. Duplančić, K. Passek-Kumerički, B. Pire, L. Szymanowski, and S. Wallon, “Probing axial quark generalized parton distributions through exclusive photoproduction of a γ π ± pair with a large invariant mass,” JHEP 11 (2018) 179, arXiv:1809.08104 [hep-ph].
[3] G. Duplančić, S. Nabeebaccus, K. Passek-Kumerički, B. Pire, L. Szymanowski and S. Wallon, “Accessing GPDs through the exclusive photoproduction of a photon-meson pair with a large invariant mass,” [arXiv:2212.01034 [hep-ph]]

Speaker: Saad Nabeebaccus (IJCLab)

APS-hadronic-meeting-Nabeebaccus.pdf

10:50 AM Accessing structure of protons and nuclei at small x at the Electron-Ion Collider

Determining the structure of protons and nuclei at high energy is one of central goals of the heavy-ion collisions and the future Electron-Ion Collider (EIC). To extract the proton shape fluctuations from HERA exclusive vector meson production data, we apply Bayesian inference and determine probabilistic constraints on the parameters describing the fluctuating structure of protons at high energy. We employ the color glass condensate framework, supplemented with a model for the spatial structure of the proton, along with experimental data from the ZEUS and H1 Collaborations on coherent and incoherent diffractive vector meson production in e+p collisions at HERA. We find out that this experimental data constrains most model parameters well. We also demonstrate that the complementary constraints can be obtained from hydrodynamic simulations of Pb+Pb collisions at the LHC.
For electron+nucleus collisions, we find out that the average nuclear geometric deformations and fluctuations affect diffractive vector meson productions, especially for the incoherent cross sections at small |t|. Also, the JIMWLK evolution doesn’t wash out this effects. We systematically study the deformations effects of Uranium, Gold, Oxygen-16, Neon-20 and isobar (Ru, Zr) on the diffractive $J/\Psi$ productions. Our work demonstrate that the future EIC diffractive data can provide direct information on the nuclear structure at small x and the complementary constraints for the nuclear geometric shape for the traditional hydrodynamic models.

Speaker: Wenbin Zhao (Wayne State University)

Wenbin_Zhao_seminar_GHP_19.pdf

11:10 AM Quark and Gluon Helicity Evolution at Small x

Resolution of the proton spin puzzle, which is inability of the constituent quark model to explain discrepancy between the spin-$1/2$ of the proton and the amount of spin carried by its quarks and gluons, as measured in experiment, is an outstanding problem in modern hadronic physics. One possibility is that "missing” spin of the proton may be found at small values of Bjorken-x. As a result, in recent years the small-x asymptotics of helicity distributions for quarks and gluons have been the subject of intense studies. In this talk we will discuss the small-x evolution of the gluon and flavour-singlet quark helicity distributions calculated in the shock-wave formalism. We will show that the helicity evolution contains mixing not only between the gluon field-strength $F_{12}$ and quark axial current $\bar{\psi}\gamma^+\gamma_5\psi$ operators, but also a sub-eikonal operator $D^i - \overleftarrow{D^i}$ which is related to the Jaffe-Manohar polarized gluon distribution. To do this, we will employ the powerful background field method which allows to unambiguously determine the form of operators and their mixing in the helicity evolution. By solving the evolution equations in the limit of large $N_c$ we find that the small-x asymptotics of the quark and gluon helicity distributions is in complete agreement with the earlier work by Bartels, Ermolaev and Ryskin.

Speaker: Andrey Tarasov (North Carolina State University)

GHP2023.pdf

11:30 AM Test beam studies of a high-granularity *SiPM-on-Tile" calorimeter insert for the EIC

We report the results of the test beam studies performed on a prototype for the high-granularity calorimeter insert for the ePIC detector at the EIC. The ECAL-sized prototype was constructed using layers of Fe absorber plates and scintillating tiles with silicon photomultipliers. A 4 GeV positron beam from Jefferson Laboratory's Hall D pair spectrometer was used to evaluate its performance. These studies serve as a proof-of-concept and will inform future design improvements and construction techniques.

Speaker: Sean Preins (University of California Riverside)

Test Beam Studies GHP.pdf

11:50 AM ePIC Overview

Speaker: Joerg Reinhold (Florida International University)

The ePIC Detector Reinhold GHP2023.pdf

10:30 AM → 12:10 PM Parallel Session: Hadron Properties and Interactions, Chair: Bill Briscoe

10:30 AM N to Delta Transition Form Factors at low momentum transfers

The first excited state of the nucleon dominates many nuclear phenomena at energies above the pion-production threshold and plays a prominent role in the physics of the strong interaction. The study of the N to ∆ transition form factors (TFFs) allows to shed light on key aspects of the nucleonic structure that are essential for the complete understanding of the nucleon dynamics. In this talk we will discuss measurements of the TFFs in Hall C at JLab, utilizing the SHMS and the HMS spectrometers, that focus on low four-momentum transfer squared where the mesonic cloud dynamics are dominant and rapidly changing.

Speaker: Hamza Atac (Temple University)

GHP23.pdf

10:50 AM K-matrix Analysis of Bottomonium in e+e- Annihilation

The first global and unitary analysis of e+e− → b ̄b cross sections is presented. We analyze exclusive cross sections in the BB ̄, B∗B ̄(+c.c.), B∗B ̄∗, Bs∗B ̄s∗, Υ(nS)π+π− and hb(nP)π+π− channels as well as the total inclusive cross section for b ̄b production. Pole positions and residues are determined for four vector states, which we associate with the Υ(4S), Υ(10750), Υ(5S) (or Υ(10860)), and Υ(6S) (or Υ(11020)). We find strong evidence for the new Υ(10750) recently claimed by Belle, although with parameters not well constrained by the data. Results presented here cast doubt on the validity of branching ratios reported earlier using Breit-Wigner parameterizations or ratios of cross sections. We also compare our results with a selection of theoretical calculations for the vector bottomonium spectrum.

Speaker: Nils Hüsken (JGU Mainz)

ghp_bbfits_nh.pdf

11:10 AM The LHCb state $P^\Lambda_{\psi s} (4338)$ as a triangle singularity

We present a model for the J/ψ Λ spectrum in B− → J/ψ Λ p ̄ decays, including the $P^\Lambda_{\psi s}(4338)$
baryon recently observed by the LHCb collaboration. We assume production via triangle diagrams
which couple to the final state via non-perturbative interactions which are constrained by heavy-
quark and SU3-flavor symmetry. The bulk of the distribution is described by a triangle diagram
with a color-favored electroweak vertex, while the sharp $P^\Lambda_{\psi s}(4338)$ enhancement is due to the ψs
triangle singularity in another diagram featuring a 1/2− baryon consistent with Σc(2800). We predict a comparable $P^\Lambda_{\psi s}(4338)$ signal in $\eta_c \Lambda$, and anticipate possible large isospin mixing effects
through decays to $J/\psi \Sigma^0$ and $η_c \Sigma^0$.

Speaker: Eric Swanson (Univ Pittsburgh)

Pc-interpretation.pdf

11:30 AM Primakoff photoproduction of eta-mesons at GlueX (PrimEx-eta experiment)

The PrimEx eta experiment aims to extract the eta radiative decay width by measuring the cross section for eta photo-production via the Primakoff Effect. This decay width will help with the determination of the eta-eta’ mixing angle and the ratio of the light quark masses. The experiment took data in Hall D at Jefferson Lab using the GlueX detector in 2019, 2021, and just recently in fall of 2022. We will describe the experimental technique, discuss the status of the experiment, and explain how we plan to extract the radiative decay width from measurement on a helium target.

This work was partially supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contracts DE-SC0013620 and DE-AC05-06OR23177.

Speaker: Viviana A Arroyave Flechas (Florida International University)

Primakoff_GHP_2023_viviana_arroyave.pdf

11:50 AM Deuteron Electro-Disintegration at Very High Missing Momenta

The deuteron electro-disintegration $D(e,e'p)n$ experiment aims to measure $D(e,e'p)n$ cross sections at high $Q^2$, $x_{Bj}>1$, and missing momenta $p_m>600$ MeV/c within a relative statistical error of 15%. To obtain a greater understanding of the strong nuclear force, we must probe deeper in the nucleus within ranges where nucleons overlap (sub-fermi distances). In this region, the nucleon-nucleon (NN) interactions are not well understood. As shown in W. Boeglin and M. Sargsian 1, there is a lack of experimental data for missing momenta beyond $500$ Mev/c. The deuteron is the simplest bound neutron-proton system which makes it the perfect starting place for understanding the strong nuclear force, especially at extremely short distances. This experiment will be conducted in the Experimental Hall C of the Thomas Jefferson National Accelerator Facility (TJNAF). CEBAF's electron beam will be incident on a liquid deuterium target and the recoil proton and electron will be detected by Hall C's High Momentum Spectrometer (HMS) and Super High Momentum Spectrometer (SHMS), respectively. The recoiled neutron momentum, i.e., neutron missing momentum, can be reconstructed from the reaction's kinematics. Within the plane wave impulse approximation (PWIA) picture the internal nucleon momenta can be directly correlated to the measured ones providing direct access the nucleon momentum distribution. However, there are other processes that can occur during the $D(e,e'p)n$ reaction, namely, final state interactions (FSI), meson exchange currents (MEC), and isobar configurations (IC) which can be suppressed with carefully selected kinematic settings 1. Results from a previous run were published by C.Yero et. al 2. This spring we will take data at higher missing momenta. We will review the experimental techniques, summarize the previous results, and, time permitting, present preliminary results from the new data.

This work was partially supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contracts DE-SC0013620 and DE-AC05-06OR23177. Gema P. Villegas was also supported by a National GEM Consortium Fellowship.

Speaker: Gema Villegas Minyety (Florida International University)

DeepPresentation_GHP23Workshop_Apr14.pdf

10:30 AM → 12:10 PM Parallel Session: Hadronization, Heavy Flavor and Jet Production, Chair: Raghav Kunawalkam Elayavalli

10:30 AM Cold Nuclear Matter Effects on Heavy Flavor Production

Heavy flavor production, both open heavy flavor and quarkonium, has been studied in a variety of systems, particularly in $p+p$, $p+A$, and $A+A$ collisions at RHIC and the LHC. The new sPHENIX detector will make important contributions to $\Upsilon$ production as well as heavy flavor jets at RHIC. The LHC experiments include both collider data and fixed-target environments. Heavy flavor production will also be studied in new and proposed lower energy fixed-target experients. Finally, heavy flavor production will be an integral part of the EIC physics program. This talk will discuss heavy flavor production with an emphasis on cold nuclear matter effects including nuclear modifications of the parton densities, multiple scattering in the medium, nucleon absorption (for quarkonium), and intrinsic charm. In particular, there have been tantalizing hints of its existence in recent years. Several experiments, either taking data or planned, could proivde definitive evidence in the next few years, see Refs. [1-3]. This talk will also introduce a new DOE topical collaboration in nuclear theory, HEFTY, that will address all aspects of heavy flavor production over the next 5 years.

[1] R. Vogt, Limits on Intrinsic Charm Production from the SeaQuest Experiment, Phys. Rev. C 103 (2021), 035204.

[2] R. Vogt, Contribution from Intrinsic Charm Production to Fixed-Target
Interactions at the LHC, to be submitted.

[3] R. Vogt, Energy dependence of intrinsic charm production: Determining the best energy forobservation, Phys. Rev. C 106 (2022) 025201.

This work was performed under the auspices of the US DoE by LLNL under
Contract DE-AC52-07NA27344 and supported by LDRD projects 21-LW-034 and
23-LW-036. This work has also been supported by the US Department of Energy, Office of Science, Office of Nuclear Physics through the Topical Collaboration in Nuclear Theory award Heavy-Flavor Theory (HEFTY) for QCD Matter.

Speaker: Ramona Vogt (LLNL/UC Davis)

GHP23_talk.pdf

10:50 AM Possible Existence of Universal Limit for Valence PDFs

We report the observation of the existence of a possible universal limit for valence parton distributions that should exist once partonic degrees of freedom are relevant for high energy scattering from strongly interacting bound systems like a nucleon, meson or few nucleon system at very short distances. Our observation is based on the notion that the Bjorken x weighted valence parton distribution function has a peak, that characterizes the average momentum fraction carried out by the valence quarks in the system. Within residual mean-field model of the valence quark distribution we found that 
the position of the peak has an universal upper limit.
We demonstrate that the existence of such limit imposes a new constraint on
choosing the starting resolution scale for valence PDFs. We also demonstrate how the existence of this limit can be used to check the onset of quark-clusters in short range nucleon correlations in nuclei.

This work is supported by the US DOE Office of Nuclear Physics Grant DE-FG02-01ER41172.

Speaker: Misak M Sargsian (Florida International University)

GHP23MisakSargsian2.pptx

GHP23MisakSargsian4.pdf

11:10 AM TMD Fragmentations from thrust dependent observables.

Extending the TMD factorization to thrust-dependent observables entails difficulties ultimately associated with the behavior of soft radiation.
In this talk, the factorization properties of the thrust distribution of $e^+e^-$ annihilation into a single hadron are discussed and their peculiarities with respect to standard TMD factorization are highlighted.
I present the phenomenological extraction of the unpolarized TMD Fragmentation Function for pions, for the first time based on a sound factorization theorem that correctly takes into account the thrust dependence in the $2$-jet region.

Speaker: Andrea Simonelli (ODU Research Foundation and JLAB)

simonelli.pdf

11:30 AM Studying hadronization mechanisms with spectator tagging of slow protons at Fermilab, Jefferson Lab, and EIC

In deep-inelastic scattering, the energetic quarks liberated from hadrons travel and interact with the nuclear medium via several processes. One of these processes is the quark energy loss induced by gluon bremsstrahlung and intra-nuclear interactions of creating future hadrons. Moreover, one manifestation of these interactions is the enhanced emission of low-energy charged particles, referred to as "grey tracks", protons with momentum between 200 and 600 MeV. Using the components of BeAGLE, the leptoproduction Monte Carlo event generator, we interpret grey track signatures of parton transport and hadron formation by initially comparing its predictions to E665 data in order to establish an important basis for future tagging studies.
With the upgrade of the PyQM module, the parton energy loss section of BeAGLE which describes the parton energy loss to the existing complement of hadronic and prehadronic interactions inside nuclei. We compare multiplicity ratios for E665 grey tracks, to the predictions of BeAGLE, varying the PyQM options and parameters to determine which physics phenomena can be identified by these data. The E665 data we used consist of multiplicity ratios for fixed-target scattering of 490 GeV muons on gaseous xenon normalized to liquid deuterium as a function of the number of grey tracks produced. We divided the data into charge and rapidity regions for charged hadrons with an average momentum of 5 GeV. The BeaGLE predictions for forward rapidities (y >2 ) agree with the data of up to 4 grey tracks per event. Beyond that range, BeAGLE overpredicts the charged particle multiplicity ratios. For backward rapidities (y<-1), BeAGLE underpredicts multiplicity ratios for positively charged particles, which are primarily protons, while providing an excellent description of negatively charged particles. Meanwhile, we observe a strong correlation between grey tracks and the in-medium path length, offering the advantage that selecting certain particles in the forward region is unlikely to bias a centrality selection. These outcomes lay a significant basis for tagging studies in CLAS and the EIC, considering grey track studies with protons or neutrons will be possible using very small momenta.

Speaker: Carolina Robles (Universidad Técnica Federico Santa María)

GHP April 2023 - Carolina ROBLES.pdf

11:50 AM Femtoscopic correlations between D0 mesons and identified hadrons in Au+Au collisions at √sNN = 200 GeV at STAR

Heavy quarks, like charm quarks, are produced early in the relativistic heavy-ion collisions and probe all stages of the evolution of the created medium – known as the Quark Gluons Plasma. Two-particle correlations at low relative momentum (the femtoscopic correlations) are sensitive to the interactions in the final state and the extent of the region from which correlated particles are emitted, the so-called region of homogeneity. A study of such correlations between charmed mesons
and identified hadrons could shed light on their interactions in the hadronic phase and the interaction of charm quarks with the bulk partons.
We will present a study of femtoscopic correlations of D0-π, D0-K, and D0-proton pairs at mid-rapidity in Au+Au collisions at √sNN = 200 GeV using data taken in the year 2014 by the STAR experiment. D0 mesons are reconstructed via the K--π+ decay channel using topological criteria enabled by the excellent track pointing resolution provided by the Heavy Flavor Tracker. We will present the femtoscopic correlation function for D0 transverse momentum above 1 GeV/c in the 0-80% centrality.

Speaker: Priyanka Roy Chowdhury (Warsaw University of Technology)

GHP-2023_Roy Chowdhury.pdf

12:10 PM → 1:40 PM Lunch

1:40 PM → 3:00 PM Plenary Session: 5, Chair: Björn Schenke

1:40 PM Origins of the GHP

I recount the early motivation for creating the GHP along with the subsequent maneuvering that was needed to overcome obstacles.

Speaker: Eric Swanson (Univ Pittsburgh)

GHP-history.pdf

2:00 PM 2022 GHP Dissertation Award: Weak decays of hadrons using high-precision lattice simulations

The leading uncertainty in obtaining precise fundamental information from particle physics experiments is often due to the difficulty of quantifying non-perturbative strong-interaction effects.

Over the last decade, Lattice QCD simulations, in which space and time are approximated by a discrete lattice of points, have improved in precision to the extent that a number of important quantities can be computed with a precision approaching, or even exceeding, 1%.

In order to make further progress in exploring the limits of the Standard Model and searching for new physics therefore, electromagnetic corrections must be included. This creates new theoretical challenges on the lattice associated with the long-range nature of the Coulomb interaction.

In this talk I will briefly review the status of lattice results for the hadronic inputs entering the amplitudes for weak decays of hadrons and motivate the need for including isospin-breaking corrections. I will then explain the theoretical framework I have been developing to include these radiative corrections and present numerical results.

Speaker: Davide Giusti (University of Regensburg)

APSGHP23_Giusti.pdf

2:30 PM 2023 GHP Dissertation Award: Heavy-flavor mesons in a hot medium

Mesons with heavy flavor content are a promising probe of the hot QCD phases produced in heavy-ion collisions. I will present our recent progress on the thermal modification of the properties of heavy mesons in hot mesonic matter. We use a self-consistent theoretical approach that employs an effective field theory based on chiral and heavy-quark spin-flavor symmetries. We apply the imaginary-time formalism to extend to finite temperature the calculation of the unitarized amplitudes of the scattering of the heavy mesons off the light mesons in coupled channels, and dress the heavy mesons with the self-energies [1,2]. We find that the open heavy-flavor ground-state spectral functions broaden and their peak is shifted towards lower energies with increasing temperatures. This has strong implications for the excited mesonic states that are generated dynamically from the heavy-light meson-meson interaction. In addition, I will briefly discuss several applications of our results. The first one corresponds to the calculation of meson Euclidean correlators using the thermal ground-state spectral functions obtained within our approach, and which we have compared with recent calculations of lattice correlators [3]. We have also computed off-shell transport coefficients implementing in-medium scattering amplitudes and the thermal dependence of the heavy-meson spectral properties, and we observe a good matching with lattice QCD data and Bayesian analyses of heavy-ion collision data at the QCD phase transition temperature [4]. Finally, we have recently studied the properties of the exotic X(3872) and X(4014) states, and their bottom counterparts, at finite temperature by incorporating the thermal spectral functions of open heavy-flavor mesons [5]. Being dynamically generated in our approach, we find that these quarkonium-like states show a decreasing mass and acquire an increasing decay width with temperature, following the trend observed in their meson constituents.

[1] G. Montaña, A. Ramos, L. Tolos and J. M. Torres-Rincon, Phys. Lett. B 806 (2020), 135464 doi: 10.1016/j.physletb.2020.135464
[2] G. Montaña, A. Ramos, L. Tolos and J. M. Torres-Rincon, Phys. Rev. D 102 (2020) 9, 096020 doi:10.1103/PhysRevD.102.096020
[3] G. Montaña, O. Kaczmarek, L. Tolos and A. Ramos, Eur. Phys. J. A 56 (2020) 11, 294 doi:10.1140/epja/s10050-020-00300-y
[4] J. M. Torres-Rincon, G. Montaña, A. Ramos and L. Tolos, Phys. Rev. C 105 (2022) 2, 025203 doi:10.1103/PhysRevC.105.025203
[5] G. Montaña, A. Ramos, L. Tolos and J. M. Torres-Rincon, arXiv:2211.01896

Speaker: Gloria Montana (Jefferson Lab)

2023_GHP_GloriaMontana.pdf

3:00 PM → 3:30 PM Break

3:30 PM → 5:15 PM Plenary Session: 6, Chair: James Dunlop

3:30 PM 2021 GHP Fellow: Studies of hadronic resonances in heavy ion collisions and how it resonates with my life

I will give an overview of the findings via the observation of hadronic resonances in heavy ion collisions from SPS to RHIC and LHC energies. The short-lived resonances are interacting through the full evolution of the collision and can be used to probe the dynamics of the partonic and hadronic matter. I started this topic with my PhD research topic at the SPS and continued with my work at the RHIC and LHC collider. Always in search for a better understanding of the QCD matter. I am very honored to be elected a Fellow of the American Physical Society in 2021 which changed my feelings of belonging and confidence in Physics. I will incorporate in my talk my personal journey and perspective on being a woman in physics on my road to the APS fellowship.

Speaker: Christina Markert (The University of Texas at Austin)

GHP_markert_pdf.pdf

4:00 PM 2021 GHP Fellow: Lattice QCD: A Journey from RHIC to EIC

I will present a short overview of some of the important developments in lattice QCD calculations in the context of relativistic heavy-ion collision experiments at RHIC. I will outline why lattice QCD calculation will play a critical role in the scientific success of the future EIC, and present some progress along these directions.

Speaker: Swagato Mukherjee (Brookhaven National Laboratory)

Mukherjee.pdf

4:30 PM 2022 GHP Fellow: Using spin to probe the structure of the universe

The intrinsic spin of fundamental particles emerges naturally from relativistic quantum mechanics, implying a deep connection between spin dynamics and the forces that ultimately shape the structure of our universe. Spin is therefore an excellent probe into the nature of complex theories, such as Quantum Chromodynamics, where the manifestation of spin correlations in dynamic objects like the proton, or the hadronization process of quarks and gluons, is not fully understood. It can also be used as a tool to probe new physics, including the measurement of the anomalous magnetic moment of the muon. This talk will discuss the speaker’s recent spin adventures, with protons and muons, and what she has learned about the universe.

Speaker: Renee Fatemi (University of Kentucky)

Fatemi_GHP_2023.pdf

5:00 PM Closing

Speaker: Bjoern Schenke (Brookhaven National Lab)

closing.pdf