Title: A High Precision Measurement of the Proton Charge Radius at JLab 

Speaker: Dr. XIONG Weizhi (Syracuse University)  

Time: 10:00am, Feb. 17 (Thursday), 2022 

Place: Room 218, Building 5  

Abstract:  

The Proton Charge Radius (PRad) Experiment was performed in 2016 in Hall B at Jefferson Lab, with both 1.1 and 2.2 GeV unpolarized electron beams. The experiment aimed to measure the e-p elastic scattering cross section under unprecedented low values of the momentum transfer squared region Q² = 2×10^-4 ~ 0.06 (GeV/c)², with a sub-percent precision. The PRad Experiment used a calorimetric method that was magnetic spectrometer free. Its detector setup included a large-acceptance, high-resolution calorimeter and two large-area, high-spatial-resolution gas electron multiplier detectors. For better control over systematic uncertainties, the absolute e-p elastic scattering cross section was normalized to that of the well-known M？ller scattering process, which was measured simultaneously with similar kinematics and detector acceptances. The windowless H2-gas-flow target used in the experiment largely removed a typical background source, the target cell windows. In this talk, I will provide a brief review for the proton charge radius puzzle, and then discuss details of the data analysis and present the PRad results.