Phys. Rev. Lett.
104,
012001
(2010)
[5 pages]
Strange Quark Contributions to Parity-Violating Asymmetries in the Backward Angle G0 Electron Scattering Experiment
D. Androić et al. (G0 Collaboration)
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D. Androić1, D. S. Armstrong2, J. Arvieux3,*, S. L. Bailey2, D. H. Beck4, E. J. Beise5, J. Benesch6, F. Benmokhtar5,7, L. Bimbot3, J. Birchall8, P. Bosted6, H. Breuer5, C. L. Capuano2, Y.-C. Chao6, A. Coppens8, C. A. Davis9, C. Ellis5, G. Flores10, G. Franklin7, C. Furget11, D. Gaskell6, M. T. W. Gericke8, J. Grames6, G. Guillard11, J. Hansknecht6, T. Horn6, M. Jones6, P. M. King12, W. Korsch13, S. Kox11, L. Lee8, J. Liu14, A. Lung6, J. Mammei15, J. W. Martin16, R. D. McKeown14, M. Mihovilovic17, A. Micherdzinska16, H. Mkrtchyan18, M. Muether4, S. A. Page8, V. Papavassiliou10, S. F. Pate10, S. K. Phillips2, P. Pillot11, M. L. Pitt15, M. Poelker6, B. Quinn7, W. D. Ramsay8, J.-S. Real11, J. Roche12, P. Roos5, J. Schaub10, T. Seva1, N. Simicevic19, G. R. Smith6, D. T. Spayde20, M. Stutzman6, R. Suleiman15,6, V. Tadevosyan18, W. T. H. van Oers8, M. Versteegen11, E. Voutier11, W. Vulcan6, S. P. Wells19, S. E. Williamson4, and S. A. Wood6 (G0 Collaboration)
1Department of Physics, University of Zagreb, Zagreb HR-41001, Croatia
2Department of Physics, College of William and Mary, Williamsburg, Virginia 23187, USA
3Institut de Physique Nucléaire d’Orsay, Université Paris-Sud, F-91406 Orsay Cedex, France
4Loomis Laboratory of Physics, University of Illinois, Urbana, Illinois 61801, USA
5Physics Department, University of Maryland, College Park, Maryland 20742, USA
6Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
7Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
8Department of Physics, University of Manitoba, Winnipeg, MB R3T 2N2 Canada
9TRIUMF, Vancouver, BC V6T 2A3 Canada
10Physics Department, New Mexico State University, Las Cruces, New Mexico 88003, USA
11LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, Grenoble, France
12Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
13Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
14Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA
15Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
16Department of Physics, University of Winnipeg, Winnipeg, MB R3B 2E9 Canada
17Jožef Stefan Institute, 1000 Ljubljana, Slovenia
18Yerevan Physics Institute, Yerevan 375036, Aremania
19Department of Physics, Louisiana Tech University, Ruston, Louisiana 71272, USA
20Department of Physics, Hendrix College, Conway, Arkansas 72032, USA
Received 29 September 2009; published 8 January 2010
We have measured parity-violating asymmetries in elastic electron-proton and quasielastic electron-deuteron scattering at Q2=0.22 and 0.63 GeV2. They are sensitive to strange quark contributions to currents in the nucleon and the nucleon axial-vector current. The results indicate strange quark contributions of ≲10% of the charge and magnetic nucleon form factors at these four-momentum transfers. We also present the first measurement of anapole moment effects in the axial-vector current at these four-momentum transfers.
© 2010 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.104.012001
DOI:
10.1103/PhysRevLett.104.012001
PACS:
13.60.-r, 11.30.Er, 14.20.Dh, 25.30.Bf
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