Moller Polarimetry for the Qweak Experiment
The Standard Model of particle physics has been extremely successful in describing particle interactions in a wide-ranging regime of energy scales. Low-energy, parity-violating experiments enable high-precision experimental tests of Standard Model predictions. Currently, Jefferson Lab is performing one such investigation to determine the weak charge of the proton, Qweak, to 4\% precision using ep scattering. By making a precise measurement of the weak charge, this experiment will provide tighter constraints on some classes of ``new physics'' at 2 TeV or higher. To calculate the parity-violating asymmetry and determine Qweak one needs precise knowledge of the incoming electron beam polarization. The Qweak experiment, which is underway in Jefferson Lab's Hall C, uses both M{\o}ller and Compton polarimetry to determine the 1 GeV beam polarization. The Hall C M{\o}ller polarimeter is particularly relevant as it uses a superconducting magnet to saturate thin, pure iron, foils out of plane. This provides precise measurements of beam polarization to within 1\% uncertainty. Since the addition of the Compton device the M\o ller polarimeter has undergone a re-commissioning phase, followed by myriad studies to reduce the systematic errors to the 0.57\% level required by Qweak. A brief overview of the Hall C M{\o}ller device, followed by preliminary results of these studies and of the Spring 2011 experiment run, will be provided.
- 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:
- 1994792
- Report Number(s):
- JLAB-PHY-11-1591; DOE/OR/23177-6940
- Resource Relation:
- Conference: 78th SESAPS Meeting 2011, Roanoke, VA, October 19, 2011
- Country of Publication:
- United States
- Language:
- English
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