Category: Awards and Recognition

On June 3rd, Erin defended her PhD thesis, titled, “Probing the Isospin Composition of Short-Range Correlated Pairs at Jefferson Lab Hall B.” Erin’s graduate work encompassed a number of projects, all related to the phenomenon of “np-dominance,” the phenomenon that short-range correlated pairs are much more likely to form between a proton and neutron, rather than two protons or two neutrons. In addition to analyzing data from the CLAS e2a experiment, performing theory calculations using Generalized Contact Formalism, Erin was one of the leaders of the team that conducted the CLAS12 short-range correlations experiment in 2021–22, and helped to calibrate and analyze the data. Erin’s particular focus was on neutron detection. She applied her skills in machine learning to study the problem of discriminating signals produced by real neutrons from those produced by spurious charged particles (an example from Erin’s thesis is shown in the event display below). Erin was able train her machine learning models using samples of data from exclusive reactions, in which the neutron’s momentum vector could be inferred from other detected particles (see figure below, right).

Erin received her B.S. in physics from Le Moyne College in 2013, and her M.S. in physics from the University of Maryland. She joined the GWU Jefferson Lab Group in 2020 as a Columbian Distinguished Fellow. This year, she was named the Physics Department’s winner of the 2024 Berman Prize for excellence in experimental physics. Beyond her scientific accomplishments, Erin contributed in so many positive ways to this group, through her leadership, her mentorship, her fostering of a supportive team environment, and especially her tenacity at every physics problem she faced. As she moves to the next stage of her career she will be missed by all of us.

This year, three graduate students in our group have won outside fellowships supporting their research into short-range correlations and hadron-structure modification in the nuclear medium. That three different agencies all elected to fund our students’ proposals speaks both to the talent and productivity of our students as well as the importance of their work.

Erin Seroka wins a 2022-23 Jefferson Lab JSA Graduate Fellowship

Erin was named one of the winners of a 2022-23 Jefferson Lab JSA Graduate Fellowship, supporting her work investigating the isospin structure of short range correlations. Erin hopes to show that the observed rise in prevalence of proton-proton short-range correlations with missing momentum is accompanied by a decrease in the prevalence of proton-neutron short range correlations. Her analysis of data from the CLAS12 Short-Range Correlations Experiment has required a huge investment of time and effort into understanding the performance of the CLAS12 Central Neutron Detector, and has made her one of the collaboration experts on that detector.

Sara Ratliff wins a 2022-23 Center for Nuclear Femtography Graduate Fellowship

Sara has won a fellowship from the Center for Nuclear Femtography supporting her work researching the motion of quarks inside bound protons and neutrons. Sara’s research uses the novel technique of “spectator recoil tagging,” using the simultaneous detection of a neutron that was merely a spectator to a nearby violent deep inelastic scattering collision to learn about the initial state of the struck nucleus or nucleon. Sara uses the CLAS12 Backward Angle Neutron Detector (BAND) to detect neutrons and has become a critical member of BAND team, working understand the efficiency and performance of the detector.

Phoebe Sharp wins a 2022-23 US Dept. of Energy, Office of Science Graduate Fellowship

Phoebe was named one of the winners of the 2022-23 US. Department of Energy Office of Science Graduate Research Fellowships, supporting her proposal to learn about short range correlations using the novel technique of rho meson photo-production. Instead of using the conventional method of quasi-elastic electron scattering to break up a short-range correlated nucleon-nucleon pair, Phoebe’s thesis experiment used a high energy photon beam. Phoebe is investigating signatures of pair break-up through the detection of a highly unstable rho-0 meson. Short-range correlations have never been observed in photon-induced reactions, and Phoebe hopes not only to break new ground in detection, but also confirm that previously seen properties of short-range correlations are in fact “reaction independent.”

Check out this profile of Gabe and his research, by GW’s Columbian College of Arts and Sciences.

It was recently announced that Phoebe Sharp is one of the 2021/22 JSA/JLab Graduate Fellows. Phoebe won the award based both on her academic achievements and on the strength of her proposal, to use a real photon beam to probe short range correlations in nuclei. She is the first fellow from GW since 2017/18.

Today, our group celebrates our newest doctor! Giovanni Angelini successfully defended his PhD thesis, titled “Probing Quark Dynamics in Semi-Inclusive Charged Pion Electroproduction with CLAS12.” This was an immensely impressive piece of work that charted both beam single-spin asymmetries as well as pion multiplicities over four-dimensional phase space. These results are some of the first to come from the CLAS collaboration after the 12 GeV upgrade, and are well on their way to publication. In fact, the π+ beam spin asymmetry results are already on the arXiv (arXiv:2101.03544 [hep-ex]) and are undergoing peer review.

We are also thrilled that Dr. Angelini has accepted a lecturer position in the physics department at American University! We wish both for his continued to success and that we’ll see him around town this fall.

Gabe Grauvogel has been awarded a Luther Rice Undergraduate Research Fellowship to support his summer research project, “Optimizing the Design of a Cherenkov Detector for a New Two-Photon Exchange Experiment.” He is one of twelve undergraduates to receive the award, and one of two from the GW Physics and Astronomy department.