Bulletin of the American Physical Society
APS April Meeting 2019
Volume 64, Number 3
Saturday–Tuesday, April 13–16, 2019; Denver, Colorado
Session R09: Proton Charge Radius and Low-Energy Properties.
1:30 PM–2:54 PM,
Monday, April 15, 2019
Sheraton Room: Governor's Square 11
Sponsoring Units: GHP DNP
Chair: Tim Hobbs, Southern Methodist University
Abstract: R09.00001 : The Proton Charge Radius Experiment (PRad) at JLab*
1:30 PM–1:42 PM
In order to investigate the proton charge radius puzzle,
the PRad experiment (E12-11-106) was performed in 2016 in Hall B at Jefferson Lab, with both 1.1 and 2.2 GeV electron beams. It aims to measure the e-p elastic scattering cross section in an unprecedented low values of momentum transfer squared region (Q2 = 2×10-4∼0.06 (GeV/c)2) with a sub-percent precision. The PRad experiment utilizes a calorimetric method that is magnetic spectrometer free. Its setup includes a large acceptance and high resolution calorimeter (HyCal), and two large area, high spatial resolution Gas Electron Multiplier (GEM) detectors. To have a better control over the systematic uncertainties, the absolute e-p elastic scattering cross section is normalized to that of the well-known Møller scattering process, which was measured simultaneously within similar kinematics and acceptances. The windowless H2-gas-flow target utilized in the experiment largely removes a typical background source, the target cell windows. In this talk, we will discuss details of the data analysis and present the proton charge radius result.
*This work is supported in part by the NSF MRI award PHY-1229153, the U.S. Department of Energy under Contract No. DE-FG02-03ER41231, Thomas Jefferson National Laboratory and Duke University
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