Early Results from the Qweak Experiment
Abstract
A subset of results from the recently completed Jefferson Lab Qweak experiment are reported. This experiment, sensitive to physics beyond the Standard Model, exploits the small parity-violating asymmetry in elastic ep scattering to provide the first determination of the protons weak charge Qweak(p). The experiment employed a 180 uA longitudinally polarized 1.16 GeV electron beam on a 35 cm long liquid hydrogen target. Scattered electrons corresponding to Q2 of 0.025 GeV2 were detected in eight Cerenkov detectors arrayed symmetrically around the beam axis. The goals of the experiment were to provide a measure of Qweak(p) to 4.2 percent (combined statistical and systematic error), which implies a measure of sin2(thetaw) at the level of 0.3 percent, and to help constrain the vector weak quark charges C1u and C1d. The experimental method is described, with particular focus on the challenges associated with the worlds highest power LH2 target. The new constraints on C1u and C1d provided by the subset of the experiments data analyzed to date will also be shown, together with the extracted weak charge of the neutron.
Cite
@article{arxiv.1311.6437,
title = {Early Results from the Qweak Experiment},
author = {D. Androic and D. S. Armstrong and A. Asaturyan and T. Averett and J. Balewski and J. Beaufait and R. S. Beminiwattha and J. Benesch and F. Benmokhtar and J. Birchall and R. D. Carlini and G. D. Cates and J. C. Cornejo and S. Covrig and M. M. Dalton and C. A. Davis and W. Deconinck and J. Diefenbach and J. F. Dowd and J. A. Dunne and D. Dutta and W. S. Duvall and M. Elaasar and W. R. Falk and J. M. Finn and T. Forest and D. Gaskel and M. T. W. Gericke and J. Grames and V. M. Gray and K. Grimm and F. Guo and J. R. Hoskins and K. Johnston and D. Jones and M. Jones and R. Jones and M. Kargiantoulakis and P. M. King and E. Korkmaz and S. Kowalski and J. Leacock and J. Leckey and A. R. Lee and J. H. Lee and L. Lee and S. MacEwan and D. Mack and J. A. Magee and R. Mahurin and J. Mammei and J. Martin and M. J. McHugh and D. Meekins and J. Mei and R. Michaels and A. Micherdzinska and A. Mkrtchyan and H. Mkrtchyan and N. Morgan and K. E. Myers and A. Narayan and L. Z. Ndukum and V. Nelyubin and Nuruzzaman and W. T. H van Oers and A. K. Opper and S. A. Page and J. Pan and K. Paschke and S. K. Phillips and M. L. Pitt and M. Poelker and J. F. Rajotte and W. D. Ramsay and J. Roche and B. Sawatzky and T. Seva and M. H. Shabestari and R. Silwal and N. Simicevic and G. R. Smith and P. Solvignon and D. T. Spayde and A. Subedi and R. Subedi and R. Suleiman and V. Tadevosyan and W. A. Tobias and V. Tvaskis and B. Waidyawansa and P. Wang and S. P. Wells and S. A. Wood and S. Yang and R. D. Young and S. Zhamkochyan},
journal= {arXiv preprint arXiv:1311.6437},
year = {2015}
}
Comments
8 pages, 4 figures, INPC2013