CNUGS 2026

May 26, 2026, 7:30 AM → Jun 12, 2026, 9:00 PM US/Eastern

CEBAF Center Rm. F113 (Jefferson Lab)

he Christopher Newport University Graduate Summer Workshop in Nuclear and Hadronic Physics (CNUGS) is the evolution of the long-running Hampton University’s HUGS program and will launch its expanded format beginning in 2026. This reimagined three-week summer workshop will continue HUGS’ and Jefferson Lab’s tradition of advanced training in fundamental nuclear and hadronic physics while introducing new curriculum elements in artificial intelligence, machine learning and data science, including an integrated AI/ML bootcamp and collaborative hackathon.

CNUGS is designed for nuclear and particle physics graduate students who have finished their coursework and have at least one year of research experience in these fields. Students who are well into a research project are also encouraged to apply. The program is simultaneously intensive, friendly, and casual. All lecturers are internationally renowned and leaders in their fields. Acceptance into the program is competitive, and a limited number of scholarships is available.

Organizing Committee:

• Alberto Accardi (CNU & JLab) - Director
• William Phelps (CNU & JLab) - Director
• Bernice Whitehead (JLab) - School Administrator

 

 

Tue, May 26

7:30 AM Check-in & Breakfast

Welcome: to Jlab

1 Welcome to JLab

Speaker: David Dean (TJNAF)

Welcome: to CNUGS

2 Welcome to CNUGS

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

Welcome 2026.pdf

Welcome: Environment, Safety, and Health

3 Environment, Safety, and Health

Speaker: Jennifer Williams (JLAB)

CNUGS ES&H.pptm

Welcome: Fostering a Positive and Respectful Workplace

4 Fostering a Positive and Respectful Workplace

Speaker: Lisa Surles-Law (Jefferson Lab)

2025 Fostering a Positive and Respectful Workplace_05.26.26.pptx

Welcome: Group photo

Welcome: Badging

12:00 PM Lunch

Intro to QCD and small-x physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

5 Intro to QCD - Lecture 1

Speaker: Ming Li (Hampton)

lecture1_QCD_Fundamentals.pdf

2:30 PM Break

Intro to QCD and small-x physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

6 Intro to QCD - Lecture 2

Speaker: Ming Li (Hampton)

lecture2_DIS_part1.pdf

3:45 PM Discussion

Wed, May 27

Hadron Spectroscopy

Convener: CHAIR: Frank Vera (Jefferson Lab)

7 Hadron Spectroscopy - Lecture 1

Speaker: Justin Stevens (College of William and Mary)

Breit Wigner exercise

stevensCNUGS_day1.pdf

10:00 AM Break

Hadron Spectroscopy

Convener: CHAIR: Frank Vera (Jefferson Lab)

8 Hadron Spectroscopy - Lecture 2

Speaker: Justin Stevens (College of William and Mary)

11:15 AM Discussion

11:30 AM Lunch

Jefferson Lab Science: Accelerator & Physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

9 Jefferson Lab Science: Accelerator

Speaker: Ryan Bodenstein (Thomas Jefferson National Accelerator Facility)

CNUGS_VirtualTour_2026 1.pptx

2:30 PM Break

Jefferson Lab Science: Accelerator & Physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

10 Jefferson Lab Science: Physics

Speaker: Dr Douglas Higinbotham (Jefferson Lab)

CNUGS-Higinbotham-2026.pptx

PXL_20260516_150550051.jpg

3:45 PM Discussion

CNUGS Ice cream social @ CNU

Convener: CHAIR: Pia Jones Petrak (JLab)

Thu, May 28

Hadron Spectroscopy

Convener: CHAIR: Pia Jones Petrak (JLab)

11 Hadron Spectroscopy - Lecture 3

Speaker: Justin Stevens (College of William and Mary)

Amplitude interference exercise

stevensCNUGS_day2.pdf

10:00 AM Break

Hadron Spectroscopy

Convener: CHAIR: Pia Jones Petrak (JLab)

12 Hadron Spectroscopy - Lecture 4

Speaker: Justin Stevens (College of William and Mary)

11:15 AM Discussion

11:30 AM Lunch

Intro to QCD and small-x physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

13 Intro to QCD - Lecture 3

Speaker: Ming Li

lecture3_DIS_part2.pdf

2:30 PM Break

Intro to QCD and small-x physics

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

14 Intro to QCD - Lecture 4

Speaker: Ming Li

lecture4_DIS_small_x.pdf

3:45 PM Discussion

Recap with speakers

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

Fri, May 29

AI/ML Bootcamp

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

15 AI/ML Bootcamp 1

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-bootcamp-1-su26.pdf

10:00 AM Break

16 AI/ML Bootcamp 1

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

11:30 AM Lunch

JLab Tour

17 JLab Tour

JLab_Tour_Agenda.png

Mon, June 1

Lattice QCD

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

18 Lattice QCD - Lecture 1

Speaker: Kostas Orginos (William and Mary / JLab)

10:00 AM Break

Lattice QCD

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

19 Lattice QCD - Lecture 2

Speaker: Kostas Orginos (William and Mary / JLab)

11:15 AM Discussion

11:30 AM Lunch

Mechanical Properties of Hadrons

Convener: CHAIR: Pia Jones Petrak (JLab)

20 Mechanical Properties of Hadrons - Lecture 1

Speaker: Adam Freese (Jefferson Lab)

Freese_2026.06.01-CNUGS.pdf

2:30 PM Break

Mechanical Properties of Hadrons

Convener: CHAIR: Frank Vera (Jefferson Lab)

21 Mechanical Properties of Hadrons - Lecture 2

Speaker: Adam Freese (Jefferson Lab)

3:45 PM Discussion

The Prad Experiment

Convener: CHAIR: Frank Vera (Jefferson Lab)

4:00 PM Discussion

22 The Prad Experiment

Speaker: Tyler Hague (JLab)

PRad-II.pdf

Tue, June 2

Lattice QCD

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

23 Lattice QCD - Lecture 3

Speaker: Kostas Orginos (William and Mary / JLab)

10:00 AM Break

Lattice QCD

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

24 Lattice QCD - Lecture 4

Speaker: Kostas Orginos (William and Mary / JLab)

lecture-4.pdf

11:15 AM Discussion

11:30 AM Lunch

AI/ML Bootcamp

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

25 AI/ML Bootcamp 2

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

2:30 PM Break

AI/ML Bootcamp

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

26 AI/ML Bootcamp 2

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-bootcamp-2-su26.pdf

3:45 PM Discussion

Wed, June 3

Global QCD Analysis

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

ZhiteYu_cnugs2_PDF-global-analysis.pdf

27 Global QCD Analysis - Lecture 1

Speaker: Zhite Yu (Brookhaven National Laboratory)

ZhiteYu_cnugs1_PDF-Factorization.pdf

10:00 AM Break

Global QCD Analysis

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

ZhiteYu_cnugs2_PDF-global-analysis.pdf

28 Global QCD Analysis - Lecture 2

Speaker: Zhite Yu (Brookhaven National Laboratory)

ZhiteYu_cnugs2_PDF-global-analysis.pdf

11:15 AM Discussion

11:30 AM Lunch

Mechanical Properties of Hadrons

Convener: CHAIR: Pia Jones Petrak (JLab)

29 Mechanical Properties of Hadrons - Lecture 3

Speaker: Adam Freese (Jefferson Lab)

2:30 PM Break

Mechanical Properties of Hadrons

Convener: CHAIR: Pia Jones Petrak (JLab)

30 Mechanical Properties of Hadrons - Lecture 4

Speaker: Adam Freese (Jefferson Lab)

3:45 PM Discussion

CNUGS Ice cream social @ CNU

Convener: CHAIR: Pia Jones Petrak (JLab)

Thu, June 4

Partiy Violation at JLab and Beyond

Convener: CHAIR: Pia Jones Petrak (JLab)

31 Partiy Violation at JLab and Beyond - Lecture 1

Speaker: Krishna Kumar (University of Massachusetts, Amherst)

CNUGS26lect1_Kumar.pdf

higgs-4l-FloatingScale-NoMuProf2.gif

10:00 AM Break

Partiy Violation at JLab and Beyond

Convener: CHAIR: Pia Jones Petrak (JLab)

32 Partiy Violation at JLab and Beyond - Lecture 2

Speaker: Krishna Kumar (University of Massachusetts, Amherst)

CNUGS26lect2_Kumar.pdf

11:15 AM Discussion

11:30 AM Lunch

AI/ML Bootcamp

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

33 AI/ML Bootcamp 3

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

2:30 PM Break

AI/ML Bootcamp

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

34 AI/ML Bootcamp 3

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-bootcamp-3-su26.pdf

3:45 PM Discussion

Recap with speakers

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

Fri, June 5

Partiy Violation at JLab and Beyond

Convener: CHAIR: Frank Vera (Jefferson Lab)

35 Partiy Violation at JLab and Beyond - Lecture 3

Speaker: Krishna Kumar (University of Massachusetts, Amherst)

CNUGS26lect3_Kumar.pdf

10:00 AM Break

Partiy Violation at JLab and Beyond

Convener: CHAIR: Frank Vera (Jefferson Lab)

36 Partiy Violation at JLab and Beyond - Lecture 4

Speaker: Krishna Kumar (University of Massachusetts, Amherst)

CNUGS26lect4_Kumar.pdf

11:15 AM Discussion

11:30 AM Lunch

Global QCD Analysis

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

ZhiteYu_cnugs2_PDF-global-analysis.pdf

37 Global QCD Analysis - Lecture 3

Speaker: Zhite Yu (Brookhaven National Laboratory)

ZhiteYu_cnugs3_Exclusive-process-GPD.pdf

2:30 PM Break

Global QCD Analysis

Convener: CHAIR: Bhawani Singh (Jefferson Lab)

ZhiteYu_cnugs2_PDF-global-analysis.pdf

38 Global QCD Analysis - Lecture 4

Speaker: Zhite Yu (Brookhaven National Laboratory)

3:45 PM Discussion

Mon, June 8

Spin structure from Jlab to the LHC

Convener: CHAIR: Ming Li

39 Spin structure from Jlab to the LHC - Lecture 1

Speaker: Charlotte Van Hulse (Free University Brussels)

CNUGS_spinlecturesI.pdf

10:00 AM Break

Spin structure from Jlab to the LHC

Convener: CHAIR: Ming Li

40 Spin structure from Jlab to the LHC - Lecture 2

Speaker: Charlotte Van Hulse (Free University Brussels)

11:15 AM Discussion

11:30 AM Lunch

AI/ML Bootcamp

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

41 AI/ML Bootcamp 4

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

2:30 PM Break

AI/ML Bootcamp

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

42 AI/ML Bootcamp 4

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-bootcamp-4-su26.pdf

3:45 PM Discussion

Tue, June 9

Light Dark Matter Searches

Convener: CHAIR: Pia Jones Petrak (JLab)

43 Light Dark Matter Searches - Lecture 1

Speaker: Marco Battaglieri (INFN-GE)

battaglieri-LightDarkMatter-CNUGS.pdf

10:00 AM Break

Light Dark Matter Searches

Convener: CHAIR: Pia Jones Petrak (JLab)

44 Light Dark Matter Searches - Lecture 2

Speaker: Marco Battaglieri (INFN-GE)

11:15 AM Discussion

11:30 AM Lunch

Spin structure from Jlab to the LHC

Convener: CHAIR: Ming Li

45 Spin structure from Jlab to the LHC - Lecture 3

Speaker: Charlotte Van Hulse (Free University Brussels)

2:30 PM Break

Spin structure from Jlab to the LHC

Convener: CHAIR: Ming Li

46 Spin structure from Jlab to the LHC - Lecture 4

Speaker: Charlotte Van Hulse (Free University Brussels)

3:45 PM Discussion

Recap with speakers

Convener: CHAIR: Ming Li

Wed, June 10

Student Seminars

Convener: CHAIR: Pia Jones Petrak (JLab)

47 Measuring the Electromagnetic Form Factor of the Proton

Over the past three decades at Jefferson Lab, there have been multiple experiments aimed at understanding the internal structure of nucleons. This is often done by measuring the electromagnetic form factors (FF) of these nucleons, at an increasingly higher momentum transfer squared, $Q^2$. The last of these experiments is GEp-V, which aims to measure the ratio of the electromagnetic form factors of the proton, $G^{p}_{E}/G^{p}_{M}$, up to a central $Q^2$ around 11 GeV$^2$. Although there is existing data up to this $Q^2$, its uncertainty is large due to the use of the Rosenbluth separation method. Rosenbluth separation assumes one-photon exchange, but as $Q^2$ gets large, contributions from two-photon exchange are no longer negligible. An alternative approach is to use the recoil polarization method, where a polarized electron beam interacts with an unpolarized hydrogen target and a polarization transfer occurs. With this method, the effects of two-photon exchange are less severe and $G^{p}_{E}/G^{p}_{M}$ can be obtained directly from the polarization transfer ratio. Using the recoil polarization method, SBS plans to make a more accurate measurement of $G^{p}_{E}/G^{p}_{M}$.

Speaker: Benjamin Spaude (William & Mary)

cnugs2026.pptx

48 Why the η to 3π decay channels are excellent precision probes of isospin breaking and the light quark mass ratio Q.

When a meson decay violates isospin symmetry, it often signals electromagnetic or weak effects, since the strong interaction approximately conserves isospin. The decays $η→π^+π^−π^0$ and $η→3π^0$, however, are an important exception: they are hadronic decays driven primarily by strong isospin breaking from the up-down quark mass difference. Because the leading electromagnetic contribution is suppressed, η→3π provides a uniquely clean window into $m_d-m_u$​ and the light-quark mass ratio Q. This talk discusses why the decay is forbidden in the exact isospin limit, how the Standard Model quark-mass term makes it possible, and how branching fractions and Dalitz plot distributions connect experimental measurements to low-energy QCD.

Speaker: Payton Arber (The George Washington University)

η_3pi_cnugs_presentation.pdf

η_3pi_cnugs_presentation.pptx

49 Gravitational Form Factors of the Unitary Fermi Gas from Lattice Effective Field Theory

The strongly coupled regime of quantum many-body physics continues to pose a formidable challenge in modern physics. A premier system used to explore this realm is the unitary Fermi gas (UFG), which is characterized by an infinite s-wave scattering length that leads to universal, conformal physics. While the thermodynamic and hydrodynamic properties of the UFG have been extensively studied, its internal mechanical structure remains largely unknown. In this talk, we present a proposed project to calculate the Gravitational Form Factors (GFFs) of the UFG using Lattice Effective Field Theory (Lattice EFT) and stochastic Monte-Carlo techniques. Because GFFs map directly to the matrix elements of the energy-momentum tensor, they offer a unique window into the spatial distribution of mass, and pressure within the gas. We discuss the lattice discretization of EFT of interest, so-called “pion-less EFT”, the extraction of the UFG's effective mass, the systematic uncertainties inherent to the lattice, and our proposed framework for computing the GFFs. Finally, we discuss how this same Lattice EFT framework can be extended to explore the few-body sector, specifically focusing on the emergence of Efimov states at the unitary limit.

Speaker: Hunter Duggin (University of North Carolina)

CNUGS_Talk_Duggin_PDF.pdf

CNUGS_Talk.pptx

50 Hadronic transverse momentum at CLAS

Hadronisation, a dynamic process where coloured objects transition into colourless bound states, is an important phenomenon tied to the understanding of strong interactions. Particularly, this process has a different behaviour in nuclear environments in comparison to vacuum, and this difference can be used to know more about the dynamics of the hadronising objects [1].

The hadronic transverse momentum broadening is an observable used in the study of the hadronisation process in nuclear environments. This observable can be related to the space-time development of a highly energetic quark traversing the nuclear medium before it transitions into a bound state [2, 3, 4]. The preliminary results for the first multidimensional experimental measurement of the transverse momentum broadening for positive pions, produced by lepton-nucleon deep inelastic scattering, in carbon, iron, and lead targets at Jefferson Lab’s CLAS detector with a 5.014GeV unpolarized electron beam, will be shown. In order to have a consistent identification framework to later extract hadronisation-related parameters, the particle identification scheme developed during the charged pions’multiplicity ratio analysis measurements is used to define this data sample [5].

[1] A. Accardi et al. “Hadron production in deep inelastic lepton nucleus scattering”. In: Nucl.Phys. B 484 (1997), pp. 265–282. doi:10.1016/S0375-9474(03)00670-5. arXiv:nucl-th/0211011.
[2] R. Baier et al. “Radiative energy loss and p(T) broadening of high-energy partons in nuclei”. In:Nucl.Phys.A 720 (2003) 131-156. doi: 10.1016/S0550-3213(96)00581-0. arXiv: hep-ph/9608322.
[3] B. Z. Kopeliovich et al. “Nuclear hadronization: Within or without?”In: Nucl. Phys. A 740 (2004), pp. 211–245. doi: 10.1016/j.nuclphysa.2004.04.110. arXiv: hep-ph/0311220.
[4] S. Domdey et al. “Transverse Momentum Broadening in Semi-inclusive DIS on Nuclei”. In: Nucl. Phys. A825 (2009), pp. 200–211. doi:10.1016/j.nuclphysa.2009.04.009. arXiv: 0812.2838 [hep-ph].
[5] S. Moran et al. “Measurement of charged-pion production in deep-inelastic scattering off nuclei with the CLAS detector”. In: Phys. Rev. C 105.1 (2022), p. 015201. doi: 10.1103/PhysRevC.105.015201. arXiv:2109.09951 [nucl-ex].1

Speaker: Esteban Molina (UMICH, UTFSM (previously))

Transverse Momentum Broadening in Nuclear Media at JLAB’s CLAS.odp

Transverse Momentum Broadening in Nuclear Media at JLAB’s CLAS.pptx

51 Extraction of the Charged Pion Form Factor from Electroproduction up to $Q^2 \approx 8.5~\mathrm{GeV}^2$

The pion, as the lightest meson and a quark--antiquark bound state, provides an important testing ground for understanding the transition between nonperturbative and perturbative Quantum Chromodynamics (QCD). The Jefferson Lab experiment E12-19-006 extends precision measurements of the pion form factor to $(Q^2 \approx 6~\mathrm{GeV}^2)$ and allows for measurements up to $(Q^2 \approx 8.5~\mathrm{GeV}^2)$, the highest (Q^2) achievable at Jefferson Lab. while p[revious Cornell measurements at similar (Q^2) were limited by large uncertainties and incomplete (L/T) separation.
This work focuses on the analysis of pion electroproduction data using Rosenbluth (L/T) separation techniques to extract the longitudinal virtual-photon cross section, from which the pion form factor (F_{\pi}) can be determined. The analysis includes studies of experimental and systematic uncertainties associated with the separated cross sections. Precise measurements of (F_{\pi}) at high (Q^2) provide important constraints on theoretical models such as the Vanderhaeghen--Guidal--Laget $(VGL)$ Regge model and contribute to our understanding of meson structure and QCD dynamics.

Speaker: Sameer Jain (Catholic University of America)

Cnugs_presentation_v3 - Copy.pptx

10:15 AM Break

Student Seminars

Convener: CHAIR: Pia Jones Petrak (JLab)

52 Exploring Lambda SIDIS Production in the Target and Current Fragmentation Regions

Semi-Inclusive Deep Inelastic Scattering (SIDIS) provides a powerful tool for studying nucleon structure and hadronization. In particular, Λ hyperon production is sensitive to strange-quark dynamics through its self-analyzing weak decay and spin structure. This work investigates Λ electroproduction in both the current fragmentation region (CFR) and target fragmentation region (TFR) using CLAS12 data from Jefferson Lab. In this talk, I will present the current progress in analyzing the data to study hadronization in the Lambda electroproduction channel.

Speaker: Uditha Weerasinghe (Mississippi State University)

2026-06-10-CNUGS-Seminar-Uditha-v3.pdf

53 Evolution of Dihadron fragmentation function

Dihadron fragmentation functions describes the probability of observing a pair of hadrons fragmenting from a quark. It involves an invariant scale associated to the relative internal motion of the dihadron system $M_h^2$ in addition to the overall hard scale $Q^2$. Evolution in $M_h^2$ varies continuously from nonperturbative to perturbative region. We demonstrate how to evolve Dihadron fragmentation functions in the presence of these two scales. In particular, our objective is to characterize the DIGLAP evolution of non-perturbative input distribution while simultaneously accounting for perturbative resummation in large $M_h^2$.

Speaker: KAZUKI MAKINO

Cnugs_2026_jlab.pdf

54 Solving Rate Equations for Spin-1 Vector and Tensor Polarization

In preparation for the tensor-polarized target experiment in Jefferson Lab's Hall C, running simulations to predict polarization spin-up and relaxation times would provide additional time-scale data beyond what we can get from experimentation alone. However, previous solutions to the spin-1 polarization rate change equations have made assumptions or errors that conflict with each other and our experimental data. We seek to re-solve these equations from first principles, then compare our solutions with each other and our data to test veracity. I will briefly discuss the motivation and science behind the tensor-polarized target experiment, then the specifics behind these equations and what they mean for the physics.

Speaker: Aden Whitney (University of New Hampshire)

Aden_W_CNUGS_Seminar_final.pdf

55 The Hyperion-Nucleon Interaction in Low Energy Effective Field Theory

In recent years, there has been a notable interest in investigating hypernuclear systems, which provide a unique laboratory for studying strong interactions in the strange quark sector. One of the main applications is related to the so-called "hyperon puzzle" in neutron stars, where theoretical models including hyperons predict maximum masses of \sim 1.5 M_{\odot} or less, in conflict with observations of neutron stars with masses up to \sim 2 M_{\odot}. Solving this puzzle with nuclear physics tools requires a detailed understanding of hyperon-nucleon (YN) interactions, hyperon-hyperon (YY) interactions, and three-body interactions involving hyperons and nucleons. In this talk, I will present the development of a local potential model for the \Lambda N interaction, derived using a low-energy EFT formalism that involves contact terms only. The present interaction has been derived up to next-to-leading order (NLO). I will also discuss the details of the fitting procedure to \Lambda p elastic scattering cross sections and present our results for different cutoff parameters up to 2.5 fm.

Speaker: Margherita Sagina (University of Pisa)

cnugs-seminar.pdf

56 Measurement of exclusive pi0 and eta photoproduction in the Primakoff inearly polarized photon beam at GlueX

A critical test for low-energy QCD is the decay of the neutral pion. Comparing this analytic prediction with measured data thus provides a valuable test for low energy QCD and symmetry breaking. The lifetime of the $\pi^0$ can be measured using exclusive $\pi^0$ photoproduction in the Coulomb field of a nucleus, referred to as the Primakoff effect. Using this technique, the PrimEx-I and II experiments found a combined radiative width measurement of 7.806 ± 0.117 eV, which agrees with the chiral anomaly prediction within 0.72%, however there is tension with NLO calculations at the level of 2 standard deviations. Exclusive π0 and η photoproduction were observed during the Charged Pion Polarizability experiment at JLab’s Hall D, which utilized a linearly polarized 4.3-12 GeV photon beam incident on a $^{208}$Pb target. Exclusive $\pi^0$ and $\eta$ photoproduction yields between 0-2.5° lab angle have been extracted from the data. The yields are then fitted with theoretical terms convoluted with the angular resolution and experimental acceptance, π0 decay widths are extracted, and compared with the PrimEx results. We also present the first measurement of the linear polarization asymmetry for $\pi^0$ photoproduction in the Primakoff region, which is sensitive to nuclear incoherent processes and non-pseudoscalar backgrounds.

Speaker: Shannen Graham-Howard (UMass Amherst)

pi0Pres3.pdf

11:45 AM Lunch

AI/ML Bootcamp

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

57 AI/ML Bootcamp 5

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-bootcamp-5-su26.pdf

CNUGS Ice cream social @ CNU

Convener: CHAIR: William Phelps (JLab)

Thu, June 11

Student Seminars

Convener: CHAIR: Ming Li (Jefferson Lab)

58 Phi electroproduction on neutron with CLAS12

Exclusive $\phi$ meson electroproduction is a promising channel to investigate the gluonic structure of the nucleon. The objective of this analysis is to extract the cross section for $\phi$ electroproduction on the neutron using CLAS12 RG-B data collected with a deuterium target. The $\phi$ meson is reconstructed through its $K^+K^-$ decay channel.

The analysis focuses on event selection, yield extraction from invariant-mass fits, and acceptance corrections based on Monte Carlo simulations. Preliminary differential cross sections are presented in view of future comparisons with $\phi$ electroproduction on bound and free proton targets.

Speaker: Mathieu Ronayette (CEA Saclay)

cnugs.pdf

59 Cross-Section Measurement of Deuteron Electro-Disintegration At Very High Missing Momenta and Large 4-Momentum Transfers (Q^{2}) [E12-10-003]

The deuteron, as the simplest neutron-proton bound state, provides a unique opportunity as a starting point to study short-range nuclear dynamics and nucleon-nucleon interactions at high momentum transfer without any complications which usually arise from heavy atoms. At large four-momentum transfer ($Q^2 \approx 4.5~\mathrm{GeV}^2$) and Bjorken $x > 1$, E12-10-003 experiment which was conducted in Jefferson Lab experiment investigates exclusive deuteron electro-disintegration in the reaction $^2\mathrm{H}(e,e'p)n$. The reaction mechanism includes contributions from Plane Wave Impulse Approximation (PWIA), Final State Interaction (FSI), Isobar Configuration (IC) and Meson Exchange Current (MEC).
This work presents the cross-section analysis of the experimental data using theoretical and PWIA for a set of missing momenta ($P_{m}$) settings ranging from approximately 120 to 900 MeV/c, at different neutron-recoil angle ($\theta_{nq}$).
The measured cross-sections are studied as functions of missing momenta and neutron recoil angle in order to investigate the evolution of the reaction mechanism over a broad kinematic range. Comparisons between experimental data and theoretical models provide insight into the role of short-range nucleon interactions, the effects of final-state interactions, and the transition from low to high-momentum nuclear dynamics in the deuteron at large momentum transfer.

Speaker: Pramila Pokhrel (Catholic University of America)

CNUGS_Pramila_Updated_slides.pdf

CNUGS_slides_Pramila.pdf

60 Measurements of $D^{0}$ and $D^{*}$ production in p+p collisions at $\sqrt{s}$ = 510 GeV in the STAR experiment

Measurements of heavy flavor production in proton-proton ($p+p$) collisions are critical for testing perturbative QCD (pQCD) calculations and serve as an essential baseline for studying nuclear matter effects in heavy-ion collisions. In this presentation, we will report on the production of $D^0$ and $D^*$ mesons in $p+p$ collisions at a center-of-mass energy of $\sqrt{s} = 510$ GeV, utilizing the data collected by the STAR experiment at RHIC in 2017.

These charmed mesons are reconstructed via their hadronic decay channels, specifically $D^0 \rightarrow K^-\pi^+$ and $D^{*+} \rightarrow D^0\pi^+ \rightarrow K^-\pi^+\pi^+$ (and their charge conjugates). The signals have been extracted over a broad kinematic range, extending down to very low transverse momentum ($p_T$) with $0 < p_T < 2.1$ GeV/$c$ for $D^0$ and $2.0 < p_T < 6.0$ GeV/$c$ for $D^*$.

This presentation presents the current status of the $D^0$ and $D^*$ measurements in p+p collisions at $\sqrt{s} = 510$ GeV reconstructed through these hadronic decay channels as performed by the STAR experiment.

Speaker: Subhadip Pal on behalf of STAR Collaboration (Czech Technical University in Prague)

seminar_CNUGS_spal.pdf

61 Overview of Resonances, K-Matrix Formalism, and Coupled-Channel Analysis in the Context of Hadron Spectroscopy

In experimental hadron spectroscopy, we are concerned with indirect measurements of short-lived bound states, known as resonances. While many of these resonances can be described within the quark model, some have quantum numbers that are forbidden by a two- or three-quark system, meaning that they must have some other internal structure. Resonances themselves are complex poles of the scattering matrix, while what we observe experimentally is constrained to the real axis of the complex plane. To extract physical values from the resonance peak, such as mass, decay width, and quantum numbers, we typically use a Breit-Wigner function to describe the pole, alongside a partial-wave analysis. However, for large decay width and/or multiple nearby resonances, this framework violates key concepts such as unitarity. One notable alternative that does not have these issues is the K-matrix formalism. The K-matrix formalism also allows for a coupled-channel analysis, where multiple different production mechanisms and decays are taken into account simultaneously. A coupled-channel analysis also has the benefit of using well-known channels to constrain less confident ones. Using data from GlueX, we plan to perform a coupled channel analysis focusing on potential exotic mesons, starting with a partial-wave analysis of $\gamma p \rightarrow pK^+K^-$. This channel has the potential for a scalar glueball, and will serve as a high confidence channel to help constrain others in the full analysis.

Speaker: Addison Kovats-Bernat (William & Mary)

CNUGS Seminar Kovats-Bernat.pdf

10:00 AM Break

Student Seminars

Convener: CHAIR: Ming Li (Jefferson Lab)

62 Coupled two- and three-body scattering amplitudes on an infinite volume

Over the past several decades, lattice quantum chromodynamics (LQCD) has developed into a powerful non-
perturbative tool for extracting hadronic scattering amplitudes from first principles. The theoretical foundation
connecting finite-volume spectra to infinite-volume scattering observables was established by Luscher for two-body
elastic scattering and has since been extended to coupled two-body channels, nonzero boost, and, more recently,
three-body systems. Of particular phenomenological interest are resonances—such as the Roper excitation, the scalar
σ/f0(500), and the exotic Tcc—that couple strongly to both two- and three-body final states. Extracting resonance
parameters in such cases requires a unified, unitary framework for the coupled 2 ↔3 system.
Prior work on coupled two- and three-body systems has relied on a non-overlap condition on kinematic cutoff
functions, which enforces an artificial separation between the support of the two- and three-body cutoff functions.
While this condition simplifies certain algebraic steps, it introduces a non-analyticity directly in the kinematic region
of interest. This issue can be resolved by constructing a diagrammatic derivation of the finite-volume quantization
condition (QC) in which the two- and three-body cuts separate naturally, without any non-overlap constraint.
The present work develops the corresponding infinite-volume (IV) side of that construction. Our main result is a
set of coupled integral equations for the 2 and 3 body scattering amplitudes, derived directly from unitarity. We set up the notation, derive the K-matrix representation, and
obtain the coupled integral equations and their decomposed form; the constraint relating K-matrix
elements to one another is also derived there. Then we describe the connection between finite-volume QC and the pipeline from lattice spectra to scattering amplitudes.

Speaker: Rana Urek

CNUGS_Rana Urek (1).key

CNUGS_Rana Urek (1).pdf

63 Two-Pion Matrix Elements in SU(2) Chiral Perturbation Theory: Analytic Structures and Implications for Lattice QCD

Two-particle matrix elements play a central role in understanding nucleon structure, for instance in determining the form factors of unstable resonances such as the ρ meson, which are nearly inaccessible experimentally. While their general features have been analyzed in various theoretical frameworks, a complete lattice-QCD determination of the corresponding amplitudes remains ongoing. Because the process involves four independent external momenta, one key difficulty lies in identifying the functional form suitable for global fits, which motivates our work.

Using SU(2) chiral perturbation theory, we study the two-pion matrix element of the electromagnetic current, relevant to the process ππ → γ* + ππ at leading (LO) and next-to-leading order (NLO), in terms of partial-wave expansions. Based on the formal structure, we isolate and subtract the pole and branch-cut contributions and extract the analytic part, which also provides a cross-check of the theoretical formalism. Our work offers intuition into the low-energy region and multi-dimensional global fitting for a full lattice QCD calculation.

Speaker: Yonggang Ren

Final_version.pdf

64 Precision Møller Polarimetry and the MOLLER Experiment at Jefferson Lab

A summary of research on precision Møller polarimetry in Hall A at Jefferson Lab. Topics include determination of polarimeter DAQ dead times, accidental coincidence corrections, and other effects. The 0.40% uncertainty goal for polarimetry in the upcoming MOLLER experiment is more stringent than for previous Hall A Experiments, necessitating such improvements. Newly determined dead time constants and corrections are presented.

Speaker: Addison Arcuri (Temple University)

PresForCNUGS2.pptx

PresForCNUGSnoAnim2.pdf

65 Using ML Methods for Energy Loss Corrections for Protons in the CLAS12 Forward Detector

Protons in the CLAS12 Forward Detector lose energy while passing through detector material, mainly through ionization, which shifts the reconstructed momentum away from the true value. This effect worsens momentum resolution and introduces biases into reconstructed kinematics, making energy loss corrections necessary for precision physics analysis.
We study machine-learning-based approaches to correct for this effect using simulated proton samples. In particular, we test supervised regression methods that learn either the true proton momentum or the momentum correction $\Delta p = p_{\mathrm{rec}} - p_{\mathrm{gen}}$ from reconstructed observables such as proton momentum and polar angle. The ML tools include dense feed-forward neural networks and gradient-boosted decision trees. We also compare different input feature sets and evaluation metrics to determine the most effective correction strategy. Model performance is assessed by comparing predicted and true proton kinematics and by studying residual distributions as functions of momentum to evaluate the stability and accuracy of the corrections in CLAS12.

Speaker: Aleksandr Bulgakov (University of Connecticut)

MLforMomCorr_Alex_Bulgakov_V3.pdf

11:15 AM Discussion

11:30 AM Lunch

Poster Session

Convener: CHAIR: Pia Jones Petrak (JLab)

66 A Survey of the ωK+Λ System in Photoproduction Data from GlueX

The GlueX experiment has accumulated the largest available data set for photoproduction studies, enabling detailed investigations of strong-interaction dynamics and searches for new resonant states. We present data collected at the Thomas Jefferson National Accelerator Facility using a linearly polarized photon beam, with a coherent peak near 9 GeV, incident on a liquid hydrogen target, and detected by the GlueX spectrometer. We focus on a survey of the largely unexplored reaction $\gamma p \rightarrow \omega K^{+}\Lambda$, which contains the vector-pseudoscalar $\omega K^{+}$ system, using the Phase-I and part of the Phase-II GlueX data set. This reaction provides a unique opportunity to study the production of strange mesons and baryons, with emphasis on searches for potential hybrid mesons in the $\omega K^{+}$ system, as well as strong-interaction dynamics in the presence of strangeness. We discuss the reconstruction and identification of this reaction and present a preliminary survey of the resulting mass spectra and differential cross sections.

Speaker: Richard Brunner (Florida State University)

Survey_of_omegaKpLambda.pdf

67 Solid Polarized Target for CLAS 12 to Study Nuclear Spin Structure Function

A robust framework measurements of spin observables in electron–nucleon
scattering were conducted at Jefferson Lab using upgraded CEBAF Large Ac-
ceptance Spectrometer(CLAS12) by Run group C (RGC). These experiments
involved the scattering of a polarized 11 GeV electron beam incident on lon-
gitudinally solid polarized nucleon targets located within CLAS12 spectrom-
eter in Hall B. The dynamically polarized target system was specifically de-
signed and optimized for operation inside CLAS12. The target polarization was
continuously monitored during data taking using Nuclear Magnetic Resonance
(NMR).In this report we discuss on the extraction of nucleon spin asymme-
tries, the Dynamic Nuclear Polarization method and discuss NMR measure-
ments needed to determine the proton polarization

Speaker: Sailaja Muduganti (Old Dominion University)

Poster Presentation.pptx (36 x 48 in) cnugs.pdf

68 Coupling experiment to accelerator control for MOLLER

Modern particle experiments require large, sophisticated machines and the expertise of many scientists and dedicated personnel. Coordinating machine performance with different, possibly competing goals for simultaneous experiments is a major challenge. To address this challenge, Jefferson Lab's Coupling Experiment to Accelerator Control (CEAC) project members will train a deep reinforcement learning model to optimize accelerator parameters, subject to experiment-specific constraints. My research in CEAC focuses on minimizing uncertainties about beam polarization for the MOLLER experiment and thereby maximizing MOLLER's discovery potential.

Speaker: Joachim Tsakanikas (University of Virginia)

CEAC_for_MOLLER.pdf

69 High-precision Compton Polarimetry for the MOLLER Experiment

The MOLLER experiment will make an ultra-high precision measurement of parity violation in electron-electron scattering as a sensitive search for new fundamental physics. Compton polarimetry provides a powerful non-invasive method to determine the polarization of high-energy electron beams with high precision. We present the design and development of a Compton polarimeter which will achieve a polarization measurement with 0.4% precision for the 11 GeV electron beam used for MOLLER. The design utilized a Fabry-Perot optical cavity storing 532~nm laser light, intersecting the electron beam. This system support control of laser polarization at the level of 0.1% and employs a helicity-reversed electron beam to determine the scattering asymmetry. The polarimeter employs both electron and photon detectors with a data acquisition system optimized for the control of systematic uncertainty in the extraction of the electron beam polarization from the scattering asymmetry. By combining precise optical control with robust detection, this system supports highly accurate of Compton-based polarization measurements and provides an essential diagnostic for precision parity -violation experiment like MOLLER.

Speaker: Xiang Zhang

70 Exclusive Vector Meson Production Beam Spin Asymmetry Extraction Techniques

Exclusive Vector Meson Production in the SIDIS kinematic Regime at Hall B of Jefferson Lab provides a unique opportunity to probe the 3D structure of the nucleon through Generalized Parton Distribution Functions (GPDs). Furthermore, by studying this production mechanism we can better understand the background to SIDIS measurements that lead to the same final state. In the channel $ep\rightarrow e\rho^+n$, the $\rho^+$ Meson decays into $\pi^+$ and $\pi^0$, which leads to the final state of $\pi^+ \gamma\gamma n$. The detection of photons and identification of the rho signal presents special challenges to this analysis. In this presentation, I will describe current progress using different techniques to extract Beam Spin Asymmetries (BSAs) for this channel.

Speaker: Tyler Hellstern (Duke University)

Hellstern_CNUGS_poster_final.pdf

71 Investigating the nuclear dependence of $R=\sigma_L/\sigma_T$ in Semi-inclusive Deep Inelastic Scattering

Semi-inclusive Deep Inelastic Scattering measurements have proven to be instrumental in providing access to flavor and transverse momentum distributions of the nucleon due to its ability to tag specific final-state hadrons in coincidence with the scattered electrons. So far, analyses in the SIDIS regime assume no nuclear dependence of the ratio $R=\sigma_L/\sigma_T$ of the longitudinal to transversely polarized virtual-photon cross section, an assumption that has not been systematically tested.
A measured nuclear dependence of $R$ would indicate that the longitudinal and transverse SIDIS responses are modified differently in the nuclear medium, providing new constrains on higher-twist effects and medium-modified hadronization mechanisms.
Experiment E-12-24-001 in Hall C will explore a possible nuclear dependence of $R$ using hydrogen, deuterium, carbon and copper data.

Speaker: Julio Gil Gutierrez (University of Tennessee)

CNUGS_2026_poster_JGG.pdf

72 Extracting N-Delta Form Factors from Neutrons Bound in He4 Nuclei

One major goal of the Low Energy Recoil Tracker (ALERT) experimental program at the Thomas Jefferson National Accelerator Facility (JLab) is to study the fundamental structure of nucleons bound in a Helium-4 nucleus. This study explores the transition of strongly bound neutrons to the first excited state of the nucleon known as the Delta resonance. The excitation is induced by scattering electrons off a liquid Helium-4 target. By measuring the scattered electron, along with the decay products of the Delta and the recoiling Helium-3 nucleus, a fully inclusive analysis of the reaction can be performed and comparisons can be made of the transition form factors to previous quasi-free measurements. The N-Delta transition form factors provide a quantitative description of how the charge and magnetization are distributed within the particles involved, and this study will shed light on how those distributions may differ for a nucleon strongly bound inside a nucleus versus an unbound nucleon. A discussion of the progress on Monte Carlo simulations on Monte that lay the groundwork for analysis of data has been presented here.

Speaker: Amitabh Biswas (New Mexico State University)

Amitabh_CNUGS_2026.pdf

73 The Search for Color Transparency

Color transparency (CT) is the suppression of final state interactions of a hadron propagating through nuclear medium when it is produced at small transverse size. The upcoming pion CT experiment plans to search for the onset of Color Transparency in pion in Hall C at Jefferson Lab. We plan to use the High Momentum Spectrometer (HMS) and the Super High Momentum Spectrometer (SHMS) in coincidence to measure the pion electroproduction cross from ${}^{1}H$, ${}^{2}H$, ${}^{12}C$, ${}^{63}Cu$ targets, from $Q^2 = 5.0 \text{ to } 8.5 (GeV/c)^2$. A signature of Color Transparency is the enhancement of nuclear transparency for larger $Q^2$ values.

Speaker: Muhammad Bedier

74 2 PION QUASI-REAL PHOTOPRODUCTION ANALYSIS AT CLAS12

The study of hadron spectroscopy and nucleon resonance structure has entered a new precision era with the 12 GeV upgrade at Jefferson Lab. The CLAS12 detector, a large-acceptance spectrometer in Hall B, provides efficient charged and neutral particle detection over a wide solid angle.
We present a preliminary analysis of the exclusive quasi-real 2 pion photoproduction, from the reaction ep → epπ⁺π⁻  where the virtuality of the exchanged photon Q² → 0. This is needed to understand the mechanisms responsible for production of meson resonances decaying into two pions. The goal of the analysis is the extraction of the differential cross sections and moments of the γp → π⁺π⁻p reaction. Selecting the properly kinematic range of the two‑pion invariant mass and momentum transfer reveals some resonances like the ρ(770) and the f2(1270).

Speaker: Marco Filippini

photoproduction_CNUGS26_poster_filippini.pdf

75 GPDs from Dilepton photonprodction

Timelike Compton Scattering (TCS), accessed through exclusive dilepton photoproduction $\gamma p \to p' \ell^+\ell^-$, is a key complementary channel to Deeply Virtual Compton Scattering (DVCS) for extracting generalized parton distributions (GPDs) from experiment. While DVCS primarily probes the imaginary part of Compton form factors, TCS provides independent access to the real part, and the combination of both channels is essential for a reliable and complete GPD extraction. However, the conventional theoretical framework for analyzing TCS relies on approximate treatments of the Bethe-Heitler (BH) mechanism, which shares the same final state but carries no GPD information. The standard approach generates an infinite series of azimuthal harmonics from the BH propagators, entangling kinematic artifacts with the GPD signal and introducing systematic bias into the extraction.

In this work, we recast TCS within the Single Diffractive Hard Exclusive Process (SDHEP) framework. Rather than treating BH as background to be subtracted, SDHEP organizes BH and TCS as different channels of the same process---a leading-power $\gamma^*$ channel and a next-to-leading-power $[q\bar{q}]$ channel---within a systematic expansion in $\sqrt{-t}/q_T$. The dedicated SDHEP frame, with its $z$-axis along the incoming photon, yields a cross section with finite azimuthal harmonics at each order in the power expansion, with no approximation of the BH propagators required. We derive the complete helicity amplitudes for both the BH and TCS subprocesses in this frame and construct the differential cross section in terms of polarization asymmetry parameters that depend linearly on GPD moments, providing an over-constrained system for GPD extraction. We show that the two frameworks are related by a simple rotation, which explains analytically how a single SDHEP harmonic maps to an infinite series in the conventional frame. Our results demonstrate that the SDHEP formalism provides a more systematic and precise pathway for extracting GPDs from current and future TCS measurements at Jefferson Lab and the Electron-Ion Collider.

Speaker: Yangli Zeng (William and Mary)

CNUGS-2026_poster_Yangli-Zeng.pdf

76 The Muon Scattering Experiment at Paul Scherrer Institute

The proton radius puzzle arises from the discrepancy between measurements of the proton charge radius obtained from muonic hydrogen spectroscopy and electron-based measurements, including electron-proton scattering and ordinary hydrogen spectroscopy. In 2010, the muonic hydrogen spectroscopy measurement reported a significantly smaller proton charge radius, differing by about 5σ from the CODATA value at the time. The Muon Scattering Experiment (MUSE) at the Paul Scherrer Institute (PSI) was designed to investigate this puzzle through simultaneous measurements of elastic electron-proton (ep) and muon-proton (μp) scattering from a liquid hydrogen target. MUSE uses the πM1 mixed secondary beam of electrons, muons, and pions at PSI, with beam momenta of 115, 160, and 210 MeV/c. Direct comparison of ep and μp cross sections provides a test of lepton universality in low Q² elastic scattering. MUSE also uses both positive and negative lepton beams to measure two-photon exchange effects, which can influence form factor and proton charge radius extraction. MUSE covers a Q² range of 0.0016–0.0820 GeV² for electrons and 0.0016–0.0799 GeV² for muons, providing sensitivity to the proton charge radius. This presentation will provide an overview of the experimental setup, current status, and recent progress of MUSE.
This work was supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DE-SC0016577.

Speaker: Nazmus Sayadat Ifat

cnugs_2026_poster_nazmus.pdf

77 Near-threshold Cross-section Determination for Coherent J/ψ Meson Photoproduction Off Deuteron

Gluons are responsible for binding quarks inside protons and neutrons through the strong interaction (QCD). Understanding how gluons are arranged spatially provides insight into how nucleons interact and how nuclear matter is held together. The investigation of near-threshold J/ψ meson photoproduction is unique opportunity to probe the gluonic structure of the nucleon and light nuclei. In particular, the reaction γd→J/ψd provides direct sensitivity to the transverse gluon distribution and gluon-mediated interaction mechanisms inside the deuteron. The transverse gluon distributions are essential for mapping the 3D internal structure of nucleons and nuclei, particularly at high energy collisions. This research aims to determine the differential and total cross sections for coherent J/ψ meson photoproduction off deuteron near threshold using untagged quasi-real photons from Jefferson Lab experiment E12-11-003B. The CLAS12 detector, located in Hall B at Jefferson Lab, operates with a 11 GeV continuous electron beam incident on a fixed liquid deuterium target. J/ψ is then produced via the exchange of a quasi-real photon and decays to a lepton pair. The J/ψ meson is identified through its leptonic decay channel, while final state particles are reconstructed and identified using particle identification (PID) methods. The four-vector of the quasi-real photon is reconstructed through four-momentum conservation. The cross-section extraction further requires background subtraction, determination of luminosity, and CLAS12 acceptance for the coherent process. The expected outcome of the proposed project will be the first determination of the near-threshold coherent J/ψ photoproduction cross section on the deuteron. This work has been supported in part by NSF PHY-2412777.

Speaker: Nishadi Silva

Poster-CNUGS 2026_Final.pdf

78 Study of the Nucleon Structure Modifications Induced by SRC Nucleon-Nucleon pairs using DVCS off neutron in Deuterium and EEEMCal Prototype Development for the EIC

Understanding nucleon structure is important, as it is one of the building blocks of the visible universe. Usually, nucleon structure is studied using electromagnetic probes, such as electrons. At low-energy Quantum Chromo-Dynamics (QCD), the study is in a non-perturbative regime. This means that it is necessary to introduce structure functions to describe the nucleon's internal dynamics. Ones of those functions are Generalized Parton Distributions (GPDs). GPDs convey an image where the transverse position and the longitudinal momentum of the partons inside the nucleon are correlated. The golden channel for accessing GPDs is Deeply Virtual Compton Scattering (DVCS), the electroproduction of a photon from one of the partons inside the nucleon. When the nucleon is in a bound state within a nucleus, such as deuterium, the partonic structure can be modified by internal nucleon-nucleon correlations, known as short-range correlations (SRC). It is likely that SRCs could be related to the well-known EMC effect. One of the experimental observables that gives access to GPDs is the Beam Spin Asymmetry (BSA). Accessing these observables requires a polarized electron beam. The CLAS12 experiment at JLab provides a polarized electron beam of up to 12 GeV suitable for DVCS measurements. Here, we present results from the analysis of DVCS off-neutron in deuterium data and the preliminary extraction of BSA. In the context of nucleon structure studies, the future Electron-Ion Collider (EIC) will provide a valuable laboratory to probe GPDs at both the quark and gluon levels. To meet the physics requirements of the EIC, the ePIC detector is being developed. The Electron Endcap Electromagnetic Calorimeter (EEEMCal) of ePIC will be composed of 2722 lead-tungstate crystals, each coupled to 16 silicon photomultipliers, with a readout chain based on HGCROC ASICs developed for the CMS experiment at the LHC. The work presented here focuses on the commissioning and characterization of the electronic readout of a 25-crystal EEEMCal prototype. In particular, we developed an ASIC-by-ASIC calibration procedure, studied the reduction of electronic noise, and measured the energy resolution as a function of LED voltage. The performance obtained with the full readout chain is compared with reference measurements performed using an oscilloscope, providing a validation of the prototype readout and its suitability for future EEEMCal studies.

Speaker: Mrs Neidy Lorena Bucuru Rodriguez (PhD Student - IJCLab JLAB/EIC Group)

BUCURU_Final_CNUGS_Poster.pdf

79 AI-Assisted Object Condensation Clustering for Calorimeter Shower Reconstruction at CLAS12

Accurate reconstruction of neutral particles (neutrons and photons) is essential for a broad range of nuclear physics measurements. However, the current COATJAVA reconstruction software at CLAS12 produces an overabundance of false neutral clusters, necessitating conservative selection cuts that reduce reconstruction efficiency. To address this limitation, we present an AI-based clustering model designed specifically for the CLAS12 electromagnetic calorimeter (ECal).
The model combines GravNet layers for local detector topology encoding with a Transformer encoder to capture long-range hit relationships, utilizing the Object Condensation framework for end-to-end cluster prediction. Evaluated on 1 million simulated e⁻+p collision events, our approach demonstrates significant improvements in particle reconstruction trustworthiness: neutron trustworthiness increases from 8.88% to 30.73%, and photon trustworthiness improves from 51.07% to 64.73%. This represents the first application of AI-based hit clustering to hodoscopic detectors at CLAS12. The model's ability to effectively suppress false clusters while maintaining detection efficiency provides a powerful tool for future physics analyses requiring precise neutral particle identification.

Speaker: Aoran Liu

Poster_AI_Clustering.pdf

80 Recoil Polarization Measurements of the Proton Elastic Electromagnetic Form Factor Ratio at High Momentum Transfer

The investigation of the spatial distributions of the charge and magnetism within nucleons remains a central problem in Hadronic Physics. The deviation from a point charge and point-like anomalous magnetic moment is characterized by introducing measurable observables as Form Factors (FFs). A clear discrepancy exists between FF ratios obtained using Rosenbluth separation and polarization transfer experiments. The results of polarization transfer experiments at the Jefferson Lab show a sharp drop in the FF ratio $\mu G_{Ep}/G_{Mp}$ starting $Q^2 \approx 1~\mathrm{GeV}^2$, pointing to a different $Q^2$ dependence of $G_{Ep}$ and $G_{Mp}$. The Super Bigbite (SBS) GEp-V experiment (E12-07-109) at the Jefferson Lab Hall A aims to extend the $Q^2$ reach of the FF ratio to $11~\mathrm{GeV}^2$. In the SBS GEp-V experiment, the Jefferson Lab's longitudinally polarized electron beam was scattered from an unpolarized liquid-hydrogen proton target, transferring polarization to the proton. The recoiling protons were detected in the Super BigBite Spectrometer, where the large dipole magnet caused spin precession, rotating the longitudinal polarization component into a normal component. The polarization components were then measured through secondary scattering in the downstream $CH_2$ analyzer. The proton-nucleus spin-orbit interaction with the analyzer material of the polarimeter result in an azimuthal asymmetry. Large-area GEM tracking detectors reconstructed the proton tracks before and after the analyzer, allowing the azimuthal asymmetry from the secondary scattering to be determined. The measured asymmetry provides access to the recoil-proton polarization components, whose ratio is directly related to the proton form factor ratio. The analysis is currently at the stage of detector calibrations. Progress is being made in optimizing software thresholds and pulse finding algorithms, Internal and Global detector alignments, and calorimeter timing and energy calibrations. An overview of the experiment and the current state of the analysis will be presented.

Acknowledgment: US Department of Energy, Office of Science, Office of Nuclear physics award number DE-FG02-03ER41240.

Speaker: Vidhura Vishvanath Nishshanka Arachchillage (Jefferson Lab SBS Collaboration)

CNUGS_POSTER_NAVV.pdf

81 Proton Charge Radius Measurement: Data-taking and Preliminary Analysis Progress of the PRad-II Experiment

The proton charge radius ($r_p$) is a fundamental quantity for understanding QCD and is essential for high-precision QED calculations. It is typically measured using hydrogen spectroscopy or elastic electron-proton (e-p) scattering. Since 2010, there has been the so-called “proton charge radius puzzle,” which arose from the results of muonic hydrogen spectroscopy. To further address the puzzle, the PRad-II experiment in Hall B at Jefferson Lab conducted an upgraded, magnetic-spectrometer-free measurement of elastic e-p scattering to extract the $r_p$. Building upon the success of the PRad experiment, which supported a smaller value of $r_p$, PRad-II aims to improve the precision by a factor of 3.5, with a total uncertainty of ~0.0043 fm. To achieve this unprecedented precision, PRad-II implemented several upgrades: a new scintillator veto detector to reach extremely low $Q^2$ values, down to the level of $10^{-5}$ $GeV^2$ at extreme forward angles, a second GEM tracking plane to improve background subtraction and vertex reconstruction, and a new fADC readout system for the high-resolution electromagnetic calorimeter. PRad-II is currently taking data in Hall B at JLab, will complete data-taking in June. In this poster, I will present the status of data-taking and some preliminary analysis results on behalf of the PRad-II Collaboration.

Speaker: Yuan Li (Shandong University)

CNUGS_poster_Yuan.pdf

Reception w/ undersecretary Gil

Fri, June 12

AI/ML Hackathon

82 AI/ML Hackathon

Speaker: William Phelps (Christopher Newport University/Jefferson Lab)

cnugs-hackathon-su26.pdf

Prizes and Farewell

Farewell 'PICNIC'