Speaker
Mr
Scott MacEwan
(University of Manitoba)
Description
The Qweak experiment at Jefferson Lab uses parity-violating electron scattering (PVES) to make a precision measurement of the proton's weak charge QpW. The experiment finished taking data in May 2012 and has reported an initial, low-statistics measurement of the asymmetry in elastic ep scattering at low Q^2 = 0.0250 (GeV/c)^2 with a beam energy of 1.16 GeV based on approximately 1/25 of the overall data collected in the experiment. Several technical challenges were overcome to successfully measure the small asymmetry including a high power liquid hydrogen target, radiation hard Cerenkov detectors, and precision electron beam polarimetry. The small Q^2 of the measurement has made possible the first determination of the weak charge of the proton, QpW, by incorporating earlier PVES data at higher Q^2 to constrain hadronic effects and the use of state-of-the art theoretical calculations. An overview of the experiment and the initial result will be presented alongside updates to the current status, including polarimetry, kinematics, backgrounds, and data quality analysis.
Primary author
Mr
Scott MacEwan
(University of Manitoba)
