SBS Semi-Inclusive Deep Inelastic Scattering Experiment E12-09-018 Re-Approved and Upgraded to "A" Rating by PAC54 | Professor Puckett's Research Homepage | Department of Physics

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

Projected results of E12-09-018 compared to existing proton and deuteron data and the prediction/uncertainty of a recent global fit. — Projected uncertainties for experiment E12-09-018 in the Sivers asymmetry for positive pion production on the neutron, compared to existing data and the prediction (with uncertainty band) of the Jam3D 2022 global fit.

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.

PAC54 closeout slide on two SBS experiments that were reviewed for jeopardy — Slide from PAC54 close-out presentation announcing recommendation of continued approval and increased scientific rating for our experiment.