2024 Joint Photonuclear Reactions and Frontiers & Careers Workshop

Aug 7, 2024, 9:00 AM → Aug 10, 2024, 7:25 PM US/Eastern

26-414 (MIT Laboratory for Nuclear Science)

Edmundo Barriga (Florida State University), Hang Qi (MIT), Bill Briscoe (GWU), Or Hen (MIT), Douglas Higinbotham (Jefferson Lab)

https://indico.jlab.org/event/869/images/166-PXL_20240809_162413699.MP-EDIT.jpg

To bring together senior researchers and early career scientists, we will be holding a joint photonuclear reactions & frontiers and careers workshop.   Talks will be schedule Aug. 7 thru Aug. 10th, 2024 at the MIT Laboratory for Nuclear Science.   The discounted room are avaliable for one additonal day, Aug. 11th, for those who wish to take a personnal day to enjoy Boston.  This workshop is in place of the Gordon conference that traditionally took place at this time.

The workshop will take place in-person at the MIT Laboratory for Nuclear Science.  

This workshop will include overview talks of the field, specific talks on state-of-the-art results, and especially for students there will be career development and scientific tools workshop (ML/AI/etc.) along with special session talks by students on their research.

As there will not be a nuclear Gordon conference this year, this workshop intends to capture as much of the spirit of the Gordon conference as possible with sufficient time for both discussions and networking.

Participants are strongly encouraged to stay at the arranged lodging:  https://mit-lns-housing.eventbrite.com

If you are planning on attending, please register and if you would like to be concidered for an invited talk please submit a title and short abstract.

Zoom Link

https://jlab-org.zoomgov.com/j/1600070311?pwd=bjXUaPKUXlRFVKQjf2XSezrrS9X6kW.1

 

Wednesday, August 7

9:00 AM Coffee

Welcome

1 Welcome and Introductions

Welcome and introductions to the Early Career & Photonuclear workshop.

Speakers: Dr Douglas Higinbotham (Jefferson Lab), Or Hen (MIT)

Talk

2 High Crimes and Misdemeanors in Data Analysis

Speaker: Dr Douglas Higinbotham (Jefferson Lab)

Doug_HighCrimes_2024.pptx

10:30 AM Coffee

Experiment

3 Introduction to Electron Scattering

This talk consists of an introduction to electron scattering

Speaker: Or Hen (MIT)

Lecture_1_eScatteringOverview.pdf

Lecture_2_EICphysicsOverview.pdf

12:00 PM Lunch

Experiment

4 History and Overview of the DOE National Lab System

I will present a history of the US national lab system from the Manhattan project to today.

Speaker: Dr Douglas Higinbotham (Jefferson Lab)

MIT-Lecture-2024.pptx

3:00 PM Coffee

Social: Freedom Trail

Thursday, August 8

9:00 AM Coffee

Theory

5 Observables for scattering on targets with arbitrary spin (25+5)

Starting from the Weinberg formalism for fields of arbitrary spin, we discuss a method for the decomposition of matrix elements of QCD operators (local currents, quark/gluon bilinears) for targets with arbitrary spin. This procedure is advantageous for the systematic study of the structure of hadrons and nuclei, particularly in the case of spin-dependent observables. As higher spin targets exhibit new features in their hadronic structure, the investigation of these properties can enhance our understanding of the strong force.

The construction allows for a unified framework to discuss spin > 1/2 very similar to the spin 1/2 case, without subsidiary conditions for the wave functions. Different types of spinors (canonical, helicity, light-front helicity) can be easily accommodated.  Its numerical implementation is simple and can be entirely reduced to objects familiar from the rotation group. A natural sl(2,C) multipole decomposition emerges, enabling a physical interpretation of non-perturbative objects that multiply spinor bilinears as Generalized Form Factors.

To demonstrate the efficacy of this method, we apply it to the description of  a spin 1 target, such as the deuteron. We discuss extensions of the formalism to hard exclusive processes on the deuteron and beyond.

*This work is supported by NSF awards 2111442, 2239274, and 2316701.

Speaker: Frank Vera (Jefferson Lab)

Obs_any_Spin_MIT2024.pdf

6 Disconnected 3-Point Functions Using Wilson Loops on the Lattice (25+5)

One of the foremost goals of research into Quantum Chromodynamics
(QCD) is to quantify the internal structure of the proton from
first principles. Ab initio calculations of QCD matrix elements
like transverse momentum distributions (TMDs) using lattice QCD
are an essential part of achieving that goal. I present first
explorations of effects on TMDs induced by the more intricate
color flows in hadron-hadron collisions compared to the standard
SIDIS and Drell-Yan processes. I analyze the correlations between
nucleon and pion two-point functions and Wilson loops computed in
lattice QCD. I consider Wilson loops of various shapes, and find
a correlation between the two-point function and Wilson loop
insertion which is significant and nonzero for narrow Wilson
loops with widths up to 3 lattice spacings (0.342 fm) for pions
and the nucleon. This disconnected quark contribution will be
combined in forthcoming work with connected three-point functions
containing non-standard Wilson gauge link structures, to assemble
the full modified TMD observables.

This research is supported by DOE Grant DE-FG02-96ER40965.

Speaker: Jacob Peyton (New Mexico State Unversity)

Disconnected 3-Point Functions Using Wilson Loops on the Lattice

10:30 AM Coffee

Career Development

7 Data Visualization

This talk will discuss how (and how not) to present data, including some amazingly good (and amazingly bad) examples. It was inspired by Edward Tufte (“The Visual Display of Quantitative Information”) and some truly terrible physics talks.

Speaker: Lawrence Weinstein (Old Dominion University)

DataVisualization2024.pptx

12:00 PM Lunch

Experiment

8 Short Range Correlations in the Nucleus (25+5)

I will discuss Short Range Correlations (SRCs) in the Nucleus.

Speaker: Andrew Denniston (MIT)

Denniston_1.pdf

9 Measurements of low energy recoils with ALERT and CLAS12 (25+5)

In my talk, I will give an overview of the experiments at Jefferson Lab's experiment hall B with the CLAS12 and ALERT detector which allows to measure low energy recoils from electron interactions with a He-4 target.
The detection of d, t and He-3 remnants from He-4 gives an opportunity to unique experiments for tagged measurements of the EMC effect, of DVCS on light nuclei and of Short-Range-Correlations. The focus of the talk will be on the approved SRC program with ALERT. Furthermore, I will show the progress in the construction and commissioning of the ALERT detector.

Speaker: Florian Hauenstein (Jefferson Lab)

Hauenstein_Alerttalk.pdf

3:00 PM Coffee

Experiment

10 EMC Effect at 11 GeV

I will report on the Jefferson Lab (JLab) Hall C experiment E12-10-008 that finished data taking in February last year. Multiple cryogenic and solid targets were used to measure inclusive electron scattering using a 10.5 GeV beam from the accelerator at JLab. The EMC effect is the phenomenon that the internal structure of the bound nucleon is different from that of a free nucleon. In this experiment, for a series of light to heavy nuclei, we measured cross section ratios at Bjorken-x<1, where the EMC effect dominates. The analysis of this data will further elucidate the connection between how quarks are distributed within the nuclei and how it relates to the nuclear density. I will outline the relevant physics, provide an overview of the experimental procedure, and present preliminary analysis results which include the first-time EMC effect results for several nuclei at large x.

Speaker: Abhyuday Sharda

EarlyCareer_Abhyuday.pdf

11 The Large Area/Acceptance Detector (LAD) experiment (25+5)

Speaker: Carlos Ayerbe Gayoso (Old Dominion University)

C.Ayerbe-LAD-20240808_compressed.pdf

12 Enhancing Precision of Signal Correction in PVES Experiments: The Impact of Bayesian Analysis on the Results of the QWeak and MOLLER Experiments

Bayesian analysis provides an essential transition from traditional frequentist methods, where probability defines the long-term frequency of events, to a framework that expresses probability as a degree of belief about the occurrence of an event or the validity of a hypothesis. This conceptual divergence is crucial in Parity Violating Electron Scattering (PVES) experiments, such as QWeak and MOLLER, where high precision is critically important.
Bayesian statistics utilize Bayes' theorem to integrate prior information and new observed data into a comprehensive posterior distribution. This approach enables direct probabilistic inferences and decision-making under uncertainty, enhancing the accuracy of experimental corrections significantly. It accounts for correlations between parameters, such as asymmetry components, by forming the posterior based on measured data, thereby providing a more accurate and realistic estimation of these parameters. Advanced computational techniques, including Hamiltonian Monte Carlo (HMC) and the No U-Turn Sampler (NUTS), are employed to efficiently navigate the complex, high-dimensional posterior distributions.
Our results demonstrate that Bayesian-fitted values align more closely with precise measurements in the Qweak experiment and simulation outcomes in the MOLLER experiment than traditional frequentist approaches. This enhanced precision is crucial for enhancing our comprehension of particle, nuclear, and hadronic physics and mitigating the impact of uncontrollable factors, including deviations in beam direction and discrepancies in spin alignment. The efficacy of Bayesian analysis in enhancing the precision of crucial experiments underscores its transformative potential in the field.
We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC).

Speaker: Elham Gorgannejad

Friday, August 9

9:00 AM Coffee

Talks F/S

13 Status of the Muon g-2 Experiment at Fermilab (25+5)

The Muon g-2 Experiment at Fermilab is on track to measure the muon magnetic anomaly to better than 140 parts-per-billion (ppb), an unprecedented level of precision. The muon's magnetic anomaly is sensitivity to all sectors of the Standard Model (SM), and thus provides a stringent test of the SM's completeness. The Muon g-2 Collaboration published its most recent result last summer (August 2023), achieving a precision of 200 ppb based on the first three years of data. Additional data from three subsequent years of running are under active analysis. In this talk, I will describe the experimental technique, detail our most recent measurement, and give a status of the ongoing analysis of our final dataset.

Speaker: Sean Foster (University of Kentucky)

MIT_Talk.pdf

MIT_Talk.pptx

14 Precision measurements at MESA (25+5)

The upcoming Mainz Energy-Recovery Superconducting Accelerator (MESA) facility at Johannes Gutenberg University Mainz will use cutting-edge accelerator technology to facilitate a range of precision electron-scattering experiments. In energy-recovery mode, MESA will generate high intensity electron beams incident on windowless gas targets, allowing clean measurements using the multipurpose MAGIX spectrometers. In extracted beam mode, the P2 experiment will use polarized electrons beams to perform high-precision measurements of parity-violating asymmetries. This talk will summarize the physics goals of MESA, with an emphasis on MAGIX and P2.

Speaker: Tyler Kutz (MIT/GW)

kutz_MESA.pdf

10:30 AM Coffee

Talks F/S

15 The case for a positron beam at Jefferson Lab (25+5)

One of the future upgrade scenarios proposed for Jefferson Lab is the addition of a positron beam capabilities. Positron scattering from hadronic targets can provide new information that cannot be accessed from electron scattering alone. Asymmetries between electron- and positron-scattering can isolate interference effects, such as those between deeply virtual Compton scattering and the Bethe-Heitler process, as well as the leading contribution from two-photon exchange. Furthermore, positron annihilation reactions allow novel searches for light dark matter. I will review these and other motivations for a positron beam and discuss the Jefferson Lab's Positron Working Group's efforts to make this upgrade a reality.

Speaker: Axel Schmidt (George Washington University)

fc2024_schmidt.pdf

16 Preliminary calculations for a two photon exchange experiment with electrons at Jefferson Lab (25+5)

Two photon exchange is one possible explanation for the disparity in the proton form factor ratio when comparing results from Rosenbluth scattering and polarization transfer experiments. To measure the effect of two photon exchange alone we intend to compare the different scattering asymmetries for electrons and positrons scattering off a polarized proton target. The asymmetry difference in these two measurements results from the sign of their charge alone, which is related solely to two photon exchange. Using a Monte Carlo simulation to account for the CLAS detector acceptance, beam shift due to the target holding field, and factoring in uncertainties from target dilution and detector resolution we are able to estimate the required beamtime to measure two photon exchange with sufficient certainty.

Speaker: August Friebolin (George Washington University)

SSA Elastic Measurement Predictions.pdf

17 SIDIS at CLAS12: Preliminary Measurements of Pion Fragmentation Functions

Presenting preliminary measurements of pion fragmentation functions

Speaker: Jason Phelan (MIT)

frontiers_sidis_2024.pdf

12:30 PM Lunch

Career Development

18 Academic Careers in the US

Advice and suggestions in seeking postdoctoral and entry-level faculty positions in US academic institutions from the point of view of a long-time chair and PI and with supplemental advice and suggestions gleaned from a recent presentation of someone who has more recently gone through the process.

Speaker: William Briscoe (GWU)

Briscoe_FandC_2024.pdf

3:00 PM Coffee

Career Development: Life After a PhD Panel

19 How to Give An Amazing Talk

Speaker: Axel Schmidt (George Washington University)

Saturday, August 10

9:00 AM Coffee

Nuclear Structure

20 Studying Short Range Correlations with rho0 Photoproduction (25+5)

Short Range Correlations (SRCs) are a feature of the internal structure of all types of nuclei. SRC pairs have been well-studied with quasi-elastic electron scattering experiments. These experiments have suggested that that SRCs can be characterized by high relative momentum and low center of mass momentum. This reliance on electron scattering, however, makes it difficult to assess the influence of reaction effects and final state interactions on our current understanding of SRCs. For that reason, the Hall D Short Range Correlations Experiment was conducted at Jefferson Lab in Fall 2021, using a real photon beam incident on nuclear targets to explore SRCs through various photoproduction channels. These channels provide insight into different kinematic regions and different final states than electroproduction experiments. My analysis has focused on rho-0 photoproduction from protons participating in SRCs, in order to test the correlations’ isospin structure. This consequently tests the predominance of np-pairing, which has widely been observed in electron scattering measurements. Our preliminary analysis shows that the predictions of Generalized Contact Formalism (GCF) work well when compared to our data set. Preliminary results of testing np-pair dominance, along with comparisons to GCF, will be presented in this talk.

Speaker: Phoebe Sharp (George Washington University)

F&C_2024.pdf

21 Nuclear structure studies using inverse kinematics experiments (25+5)

Recent experiments at JINR and GSI aim at studying long- and short-range nuclear structure in inverse kinematic experiments with nuclear beams at few GeV/c/u. I will discuss preliminary results.

Speaker: Julian Kahlbow (MIT)

jkahlbow_photonuclear2024.pdf

10:30 AM Coffee

Nuclear Structure

22 A High Luminosity Polarized Helium-3 target for various experiments in Halls A and C of Jefferson Lab (25+5)

The A1n, d2n, GEn-II and A_LL experiments at Jefferson lab utilized a high luminosity polarized He3 target for precise measurements at high x and/or Q^2 settings. The target consists of a pumping chamber (where polarization of He3 takes place), a target chamber (where e- beam interacts with the target material) and transfer tubes (which facilitate a convective flow of the polarized material). He3 gas at ~8 atm pressure is filled into the glass cells along with Rb-K alkali mixture and narrow band diode lasers are used for polarizing the He3 using a SEOP (Spin Exchange Optical Pumping) technique. The target system used in the experiment includes Helmholtz coils to create a holding field that determines the direction of polarization for the He3 nuclei. Two polarimetry techniques are used to determine the absolute (EPR) and relative (EPR) polarization during production running. Physics goals of these experiments and the overall target performance will be briefly discussed in this talk.

Speaker: Arun Tadepalli (Jefferson Lab)

MIT_Gordon_Aug10.pptx

23 Short-Range Correlations in Exotic Nuclei (25+5)

Nucleon-nucleon short-range correlations (SRCs) in atomic nuclei have traditionally been investigated using electron scattering. SRCs are predominantly found as proton-neutron pairs, as has been observed for light and heavy nuclei. We have extended SRC measurements for the first time to very neutron-rich short-lived nuclei by employing scattering of high-energy ion beams at 1.25 AGeV off a proton target in inverse kinematics at the R³B setup at GSI-FAIR (Germany). The study of nucleon-knockout reactions on $^{12}$C and $^{16}$C in fully exclusive kinematics provides unique insight into SRC properties. In this talk, I will present the experiment and discuss the measurement and preliminary results for SRC properties in $^{12}$C and $^{16}$C.

Speaker: Hang Qi (MIT)

F&C_Qi_2024.pdf

24 ρ- Meson Photoproduction as a Test of SRC Universality

Nuclear Short Range Correlations (SRCs) are pairs of nucleons which exist at short relative distance and high relative momentum within the nucleus. These SRC pairs have significant impacts on nuclear structure and have been extensively studied using hard quasi-elastic electron-scattering data. Interpretations of these hard scattering data rely heavily on our understanding of reaction mechanisms at play in electron-scattering measurements, as well as assumptions of of factorization between the reaction and the nuclear ground-state. In fall of 2021, our collaboration took data in Hall D of Jefferson Lab, using a real photon beam incident on nuclear targets to independently measure the properties of nuclear SRCs. Here we present the measurement of SRC breakup events in this data using quasi-elastic ρ- meson photoproduction from correlated neutrons in deuterium, helium, and carbon nuclei, along with comparisons to the GCF predictions. We use the ab-initio calculations to show consistency between the electron- and photo-scattering measurements; in this, we provide evidence for the universality of SRC properties across reactions, showing that several different hard reactions proceeding on correlated nucleons may be consistently explained using a single model.

Speaker: Jackson Pybus (MIT)

SRC Universality.pdf

12:25 PM Lunch

Experiment

25 Calculating Photon Transparency of Rho0 Mesons in HallD at JLab (25+5)

Experiment E12-19-003, carried out in Jefferson Lab's Hall D in 2021, aimed to explore the predicted QCD phenomenon known as Color Transparency in photons, mesons, and baryons. The experiment used low atomic mass nuclei such as helium, deuterium, and carbon targets through photoproduction. In my discussion, I will present the preliminary cross-section ratio of the ρ0 meson between the targets as a function of momentum transfer ∣t∣ (GeV2). Additionally, I will examine the methods used to remove background noise from the reconstruction of the ρ0 meson.

Speaker: Bhesha Devkota (Mississippi State Uiversity)

Fronteir_2024 (1) - Bhesha.pptx

Fronteir_2024A.pdf

26 Search for Resonances in the ωη System at GlueX (25+5)

The GlueX experiment has produced the world’s largest data sample for peripheral photoproduction of mesons with a goal to expand our understanding of the strong interaction and search for hybrid mesons. The data set was obtained at the Thomas Jefferson National Accelerator Facility utilizing the GlueX detector and a tagged linearly polarized photon beam that peaks between 8 - 9 GeV incident on a liquid hydrogen target. We will present the current status of the search for possible intermediate resonances which decay to ωη. Little is known about the established ω(1650), and the states with exotic quantum numbers JP C = 0−−, 2+− have not yet been observed. The ω, in this reaction, is identified via the π+π−π0 decay mode, and the η and π0 are identified via the decay to 2γ. We present a description of the data following an angular moment analysis approach and outline our strategy for future studies.

Speaker: Edmundo Barriga (Florida State University)

F&C_2024.pdf

3:00 PM Coffee

Experiment

27 Lead Tungstate Calorimeter for the JLab Eta Factory Experiment (25+5)

The installation of a new lead tungstate calorimeter (ECAL) insert in Hall D’s GlueX detector at Jefferson Lab (JLab) will allow for the improved reconstruction of η/η’ decay channels. The ECAL is necessary for the upcoming Jefferson Lab Eta Factory (JEF) experiment, which aims to study rare decays of eta mesons. The insert consists of 1596 lead tungstate scintillating crystals which have been installed in the center of the detector’s lead glass forward calorimeter (FCAL). My work during the summer of 2024 centered on this hardware upgrade, involving the testing of the light-monitoring system (LMS), ECAL modules, and the installation of cables and readout electronics. The detector will be ready for its first run as a part of the JEF experiment in January of 2025. I will present an overview of this new calorimeter and my contribution to the hardware upgrade in Hall D.

Speaker: Olivia Nippe-Jeakins (George Washington University)

FCAL_Upgrade.pdf

28 First Measurement of Near- and Sub-Threshold J/ψ Photoproduction off Nuclei

I will discuss the first measurement of near- and sub-threshold J/ψ photoproduction off nuclei taken in Jefferson Lab's Hall D.

Speaker: Lucas Ehinger (MIT)

JPsi Frontiers Ehinger Lucas.pdf