Recoil polarization measurements of the proton form factor ratio GpE/GpM to high Q2 in Hall C at Jefferson Lab

Conference · Fri May 01 00:00:00 EDT 2009

OSTI ID:1999643

Puckett, Andrew

Experiment E04-108 in Hall C at Jefferson Lab measured the ratio of the proton's electric ($$G_E$$) and magnetic ($$G_M$$) form factors using the recoil polarization technique at three different values of squared four-momentum transfer $Q^2$--5.2, 6.8, and 8.5 GeV$^2$. Data taking was completed in June 2008. Two new detectors were built by the collaboration to carry out this experiment. A large solid-angle electromagnetic calorimeter was used to detect elastically scattered electrons in coincidence with scattered protons detected by the Hall C High Momentum Spectrometer (HMS). The calorimeter allowed a clean rejection of the significant inelastic backgrounds present at such high $Q^2$. A new Focal Plane Polarimeter (FPP) was installed in the HMS detector hut to measure the polarization of the scattered proton. Following a discussion of the data analysis method, preliminary results will be reported.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1999643
• Report Number(s): JLAB-PHY-09-954; DOE/OR/23177-0847
• Resource Relation: Conference: 2009 APS April Meeting, May 2–5, 2009; Denver, Colorado
• Country of Publication: United States
• Language: English