Phys. Rev. Lett.
95,
092001
(2005)
[5 pages]
Strange-Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment
D. S. Armstrong et al. G0 Collaboration
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D. S. Armstrong1, J. Arvieux2, R. Asaturyan3, T. Averett1, S. L. Bailey1, G. Batigne4, D. H. Beck5, E. J. Beise6, J. Benesch7, L. Bimbot2, J. Birchall8, A. Biselli9, P. Bosted7, E. Boukobza2,7, H. Breuer6, R. Carlini7, R. Carr10, N. Chant6, Y.-C. Chao7, S. Chattopadhyay7, R. Clark9, S. Covrig10, A. Cowley6, D. Dale11, C. Davis12, W. Falk8, J. M. Finn1, T. Forest13, G. Franklin9, C. Furget4, D. Gaskell7, J. Grames7, K. A. Griffioen1, K. Grimm1,4, B. Guillon4, H. Guler2, L. Hannelius10, R. Hasty5, A. Hawthorne Allen14, T. Horn6, K. Johnston13, M. Jones7, P. Kammel5, R. Kazimi7, P. M. King6,5, A. Kolarkar11, E. Korkmaz15, W. Korsch11, S. Kox4, J. Kuhn9, J. Lachniet9, L. Lee8, J. Lenoble2, E. Liatard4, J. Liu6, B. Loupias2,7, A. Lung7, G. A. MacLachlan16, D. Marchand2, J. W. Martin10,17, K. W. McFarlane18, D. W. McKee16, R. D. McKeown10, F. Merchez4, H. Mkrtchyan3, B. Moffit1, M. Morlet2, I. Nakagawa11, K. Nakahara5, M. Nakos16, R. Neveling5, S. Niccolai2, S. Ong2, S. Page8, V. Papavassiliou16, S. F. Pate16, S. K. Phillips1, M. L. Pitt14, M. Poelker7, T. A. Porcelli15,8, G. Quéméner4, B. Quinn9, W. D. Ramsay8, A. W. Rauf8, J.-S. Real4, J. Roche7,1, P. Roos6, G. A. Rutledge8, J. Secrest1, N. Simicevic13, G. R. Smith7, D. T. Spayde5,19, S. Stepanyan3, M. Stutzman7, V. Sulkosky1, V. Tadevosyan3, R. Tieulent4, J. van de Wiele2, W. van Oers8, E. Voutier4, W. Vulcan7, G. Warren7, S. P. Wells13, S. E. Williamson5, S. A. Wood7, C. Yan7, J. Yun14, and V. Zeps11 (G0 Collaboration)
1Department of Physics, College of William and Mary, Williamsburg, Virginia 23187 USA
2Institut de Physique Nucléaire d’Orsay, Université Paris-Sud, F-91406 Orsay Cedex France
3Yerevan Physics Institute, Yerevan 375036 Armenia
4Laboratoire de Physique Subatomique et de Cosmologie, F-38026 Grenoble Cedex France
5Loomis Laboratory of Physics, University of Illinois, Urbana, Illinois 61801, USA
6Physics Department, University of Maryland, College Park, Maryland 20472, USA
7Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
8Department of Physics, University of Manitoba, Winnipeg, MB R3T 2N2 Canada
9Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
10Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA
11Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA
12TRIUMF, Vancouver, BC V6T 2A3 Canada
13Department of Physics, Louisiana Tech University, Ruston, Louisiana 71272, USA
14Department of Physics, Virginia Tech, Blacksburg, Virginia 24061, USA
15Department of Physics, University of Northern British Columbia, Prince George, BC V2N 4Z9 Canada
16Physics Department, New Mexico State University, Las Cruces, New Mexico 88003, USA
17Department of Physics, University of Winnipeg, Winnipeg, MB R3B 2E9 Canada
18Department of Physics, Hampton University, Hampton, Virginia 23668, USA
19Department of Physics, Grinnell College, Grinnell, Iowa 50112, USA
Received 17 June 2005; published 26 August 2005
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Physics
Focus
We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12≤Q2≤1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.
© 2005 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.95.092001
DOI:
10.1103/PhysRevLett.95.092001
PACS:
13.60.−r, 11.30.Er, 14.20.Dh, 25.30.Bf
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