EPJ Web of Conferences
Volume 66, 2014INPC 2013 – International Nuclear Physics Conference
|Number of page(s)||8|
|Section||Fundamental Symmetries and Interactions in Nuclei|
|Published online||20 March 2014|
Early Results from the Qweak Experiment
1 Department of Physics, University of Zagreb, Zagreb, HR 10002 Croatia
2 College of William and Mary, Williamsburg, VA 23185 USA
3 A. I. Alikhanyan National Science Laboratory (Yerevan Physics and), Yerevan 0036, Armenia
4 Massachusetts and of Technology, Boston, MA 02139 USA
5 Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 USA
6 Ohio University, Athens, OH 45701 USA
7 Christopher Newport University, Newport News, VA 23606 USA
8 University of Manitoba, Winnipeg, MB R3T2N2 Canada
9 University of Virginia, Charlottesville, VA 22908 USA
10 TRIUMF, Vancouver, BC V6T2A3 Canada
11 Hampton University, Hampton, VA 23668 USA
12 Mississippi State University, Mississippi State, MS 39762 USA
13 Virginia Polytechnic and & State University, Blacksburg, VA 24061 USA
14 Southern University at New Orleans, New Orleans, LA 70126 USA
15 Idaho State University, Pocatello, ID 83209 USA
16 Louisiana Tech University, Ruston, LA 71272 USA
17 University of Connecticut, Storrs-Mansfield, CT 06269 USA
18 University of Northern British Columbia, Prince George, BC V2N4Z9 Canada
19 University of Winnipeg, Winnipeg, MB R3B2E9 Canada
20 George Washington University, Washington, DC 20052 USA
21 University of New Hampshire, Durham, NH 03824 USA
22 Hendrix College, Conway, AR 72032 USA
23 University of Adelaide, Adelaide, SA 5005 Australia
a now at Indiana University, Bloomington, Indiana 47405, USA
b now at Institute for Basic Science, Daejeon, South Korea
c now at Rutgers, the State University of New Jersey, Piscataway, NJ 08854 USA
d e-mail: email@example.com
e now at University of Manitoba, Winnipeg, MB R3T2N2 Canada
Published online: 20 March 2014
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 scattering to provide the first determination of the proton’s weak charge . The experiment employed a 180 μA longitudinally polarized 1.16 GeV electron beam on a 35 cm long liquid hydrogen target. Scattered electrons in the angular range 6° < θ < 12° corresponding to Q2 = 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 to 4.2% (combined statisstatistical and systematic error), which implies a measure of sin2(θw) at the level of 0.3%, 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 world’s highest power LH2 target. The new constraints on C1u and C1d provided by the subset of the experiment’s data analyzed to date will also be shown, together with the extracted weak charge of the neutron.
© Owned by the authors, published by EDP Sciences, 2014
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