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Title The First Direct Measurement of the Weak Charge of the Proton
Authors John Leckey
JLAB number JLAB-PHY-12-1483
LANL number (None)
Other number DOE/OR/23177-3742
Document Type(s) (Thesis) 
Associated with EIC: No
Supported by Jefferson Lab LDRD Funding: No
  Thesis
A PHD thesis
Advisor(s) :
   David Armstrong (College of William and Mary)
Publication Abstract: Qweak is an experiment currently running at the Thomas Jefferson National Accelerator Facility that uses parity-violating elastic electron-proton scattering to measure the weak charge of the proton, QPweak . Longitudinally polarized electrons are scattered off a liquid hydrogen target and pass through a toroidal-field magnetic spectrometer. This experiment is a sensitive test for physics beyond the Standard Model, as QPweak is well predicted in the Standard Model. This dissertation describes the first direct measurement of QPweak. The precision that will be generated by the final 4% measurement will allow the probing of certain classes of new physics up to 2.5 TeV. In this dissertation, the design and status of the complete experiment are discussed, including the details of the asymmetry measurements and preliminary results from several studies of experimental systematics. This dissertation also includes a full description of the design, construction, commissioning, and use of the vertical drift chambers (VDC) used in the Qweak experiment to measure the scattered electron's profile and the momentum transfer (Q2) of the ep scattering. The Q2 was measured to be 0.0274 ± 0.0013 GeV^2/c2 and QPweak was measured to be 0.102 ± 0.036, which is consistent with the Standard Model.
Experiment Numbers: E08-016
Group: Hall C
Document: pdf
DOI:
Accepted Manuscript:
Supporting Documents:
Supporting Datasets: