The 54th meeting of Jefferson Lab’s Program Advisory Committee (PAC) was held the week of July 6-10, 2026. Experiment E12-09-018, the largest remaining fully-approved experiment using the SBS equipment in terms of beam time, faced a jeopardy review of its continued approval status and scientific rating. Every JLab experiment that has been approved but not yet scheduled must return to the PAC every ~4-5 years to ensure its continued scientific relevance/importance, a process known as “jeopardy”.

Experiment E12-09-018, of which Professor Puckett is a co-spokesperson, faced its second jeopardy review this year by PAC54 (the first having taken place at PAC49 in 2021). Professor Puckett presented the case for the continued approval and increasing scientific merit of the experiment to the PAC. Given the completion of the SBS form factor program and the increasing importance of the experiment, the PAC recommended that the experiment retain its approval status and increased its scientific rating from “A-” to “A”, which should help the experiment receive higher priority for scheduling in Hall A. Another SBS experiment, to measure the structure function of the pion via “tagged” deep inelastic scattering, retained its “C1” conditional approval status and “A-” scientific rating.

Link to PAC54 presentation slides: https://userweb.jlab.org/~puckett/PR1209018/PAC54/J12-26-001_PAC54_Puckett_final.pdf

Link to PAC54 jeopardy proposal: https://userweb.jlab.org/~puckett/PR1209018/PAC54/SBS_SIDIS_PAC54_Update_as_submitted_FINAL.pdf

Figure 1 above shows a representative example of the projected data from E12-09-018; namely, the Sivers single-spin asymmetry in the semi-inclusive production of positive pions in deep inelastic collisions on the transversely polarized neutron in Helium-3, for beam energies of 11 and 8.8 GeV, compared to existing data for proton and deuteron targets, as well as the predictions, with uncertainty bands at each energy, of the JAM3D 2022 global fit.

A new paper describing the lead-glass electromagnetic calorimeter for the BigBite spectrometer used during the recently-completed Super BigBite Spectrometer (SBS) form factor experiments was published in Nuclear Instruments and Methods Section A.

This paper is the first of many technical/instrumentation publications on the equipment used on the floor of Hall A during the SBS program, detailing the detector design and performance characteristics. This is the first SBS instrumentation paper based on actual in-beam operational experience.

The lead author is former UConn graduate student Provakar Datta, who was responsible for the calibration and operation of this detector throughout the SBS program. Other UConn co-authors include professor Puckett, former postdoc Eric Fuchey, and former graduate student Sebastian Seeds.

Link to the paper from the publisher website: https://doi.org/10.1016/j.nima.2026.171669

Link to the INSPIRE-HEP record: https://inspirehep.net/literature/3108638 

Former UConn graduate student Provakar Datta’s Ph.D. thesis was selected for the annual JSA/Jefferson Lab Thesis Prize, which included a cash prize, a plaque, and an invitation to present his research at the annual Jefferson Lab Users’ Organization Meeting (JLUO), that took place from June 24-26, 2025. This prestigious award recognizes the best Ph.D. thesis on research conducted at Jefferson Lab over the previous year, as determined by an expert committee who judged the quality of the written thesis, the importance of the results, the originality of the approach, mastery of the subject, and the contribution of the student to the research.

Link to the self-published, citeable thesis on INSPIRE.

Jefferson Lab’s Recent News Release on the award.

Provakar Datta successfully defended his thesis titled “Precision Measurements of the Neutron Magnetic Form Factor to High Momentum Transfer using Durand’s Method” on September 18, 2024. From October to December, Provakar stayed on as a postdoc in the group, before starting a new postdoctoral position at Lawrence Berkeley National Lab.

Sebastian successfully defended his thesis titled “The Two-Photon-Exchange Contribution to Electron-Neutron Elastic Scattering and Extraction of G_Mⁿ at Q² = 4.5 GeV² in Hall A at Jefferson Lab” on Friday, July 19, 2024. After completing his Ph.D., Sebastian will start a new position as Staff Scientist 2 at Los Alamos National Laboratory, in the Intelligence and Space Research Division.

The thesis can be found here: Thesis PDF

Professor Puckett traveled to Jefferson Lab in July 2024 to defend an experiment proposal developed with Professors Jan Bernauer of Stony Brook University and Axel Schmidt of George Washington University at the 52nd meeting of Jefferson Lab’s Program Advisory Committee (PAC52). PAC52 approved the proposal with an “A-” scientific rating. The proposal was to add a short (two days of beam time), opportunistic, high-precision measurement to the upcoming experiment E12-07-109 in Hall A at JLab (of which Professor Puckett is also a co-spokesperson). This short “add-on” measurement to an upcoming experiment would improve the precision of the polarization transfer data for the proton form factor ratio as measured in electron-proton scattering by a factor of four at a squared four-momentum transfer of 3.7 GeV². This improvement is necessary to enable a precise comparison to a planned future measurement using positron beams at the same or similar momentum transfer, aimed at resolving the long-standing discrepancy between cross section and polarization measurements in the determination of the proton’s form factor ratio. The precision goals are driven by the expected magnitude of two-photon-exchange contributions widely thought to be responsible for the discrepancy.

The experiment proposal as submitted to PAC52 can be found here.

Professor Puckett’s presentation to PAC52 can be found here.

The figure below shows the approved measurement compared to existing data and a planned future positron measurement at the same Q²:

Loading...

Taking too long?

Reload document

| Open in new tab

Professor Puckett gave an invited talk on the status of the ongoing data analyses from the completed SBS neutron form factor experiments at the joint Hall A/C summer workshop on July 15.

The meeting agenda can be found here.

Professor Puckett’s slides can be found here.

The “50 Years of Quantum Chromodynamics” invited review by the European Physical Journal C is now published online at the following link:

https://doi.org/10.1140/epjc/s10052-023-11949-2

Professor Puckett contributed section 10.1 on nucleon electromagnetic form factors. The review is a comprehensive history and introduction to research in QCD intended to serve as a useful reference for researchers in the field from beginning graduate students to senior physicists, as well as a snapshot of current research and future directions in the field.

Professor Puckett and UConn physics graduate students Provakar Datta and Sebastian Seeds were part of a strong contingent of Hall A SBS Collaborators at the recent APS DNP/JPS meeting on the big island of Hawaii, reporting on the progress of various data analyses and the preparations for upcoming experiments. This was the 6th Joint Meeting of the American Physical Society’s Division of Nuclear Physics (APS DNP) and the Physical Society of Japan (JPS). More information about the meeting, including the abstracts and authors, can be found at the meeting website.

Professor Puckett and UConn graduate students Provakar Datta, Sebastian Seeds, and Kip Hunt participated in the Super BigBite Spectrometer (SBS) Collaboration Meeting at Jefferson Lab on July 17-18, 2023. In the two-day meeting, talks were presented on the status of ongoing experiments, SBS equipment developments, data analysis of completed experiments, preparations for upcoming experiments, and ideas for future experiments using SBS equipment. Additionally, on the first day, Dr. Anatoly Radyushkin gave a seminar on recent developments in the calculation of the nucleon’s quark distributions in lattice gauge theory. At the end of the meeting, an “end of run party” for the first two completed experiments was held at the SURA Residence Facility.