Phys. Rev. C
69,
065501
(2004)
[35 pages]
Parity-violating electroweak asymmetry in e⃗p scattering
K. A. Aniol et al. HAPPEX Collaboration
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K. A. Aniol1, D. S. Armstrong34, T. Averett34, M. Baylac27,12, E. Burtin27, J. Calarco20, G. D. Cates24,33, C. Cavata27, Z. Chai19, C. C. Chang17, J.-P. Chen12, E. Chudakov12, E. Cisbani11, M. Coman4, D. Dale14, A. Deur12,33, P. Djawotho34, M. B. Epstein1, S. Escoffier27, L. Ewell17, N. Falletto27, J. M. Finn34,*, K. Fissum19, A. Fleck25, B. Frois27, S. Frullani11, J. Gao19,†, F. Garibaldi11, A. Gasparian7, G. M. Gerstner34, R. Gilman26,12, A. Glamazdin15, J. Gomez12, V. Gorbenko15, O. Hansen12, F. Hersman20, D. W. Higinbotham33, R. Holmes29, M. Holtrop20, T. B. Humensky24,33,‡, S. Incerti30, M. Iodice10, C. W. de Jager12, J. Jardillier27, X. Jiang26, M. K. Jones34,12, J. Jorda27, C. Jutier23, W. Kahl29, J. J. Kelly17, D. H. Kim16, M.-J. Kim16, M. S. Kim16, I. Kominis24, E. Kooijman13, K. Kramer34, K. S. Kumar24,18, M. Kuss12, J. LeRose12, R. De Leo9, M. Leuschner20, D. Lhuillier27, M. Liang12, N. Liyanage19,12,33, R. Lourie28, R. Madey13, S. Malov26, D. J. Margaziotis1, F. Marie27, P. Markowitz12, J. Martino27, P. Mastromarino24, K. McCormick23, J. McIntyre26, Z.-E. Meziani30, R. Michaels12, B. Milbrath3, G. W. Miller24, J. Mitchell12, L. Morand5,27, D. Neyret27, C. Pedrisat34, G. G. Petratos13, R. Pomatsalyuk15, J. S. Price12, D. Prout13, V. Punjabi22, T. Pussieux27, G. Quéméner34, R. D. Ransome26, D. Relyea24, Y. Roblin2, J. Roche34, G. A. Rutledge34,32, P. M. Rutt12, M. Rvachev19, F. Sabatie23, A. Saha12, P. A. Souder29,§, M. Spradlin24,8, S. Strauch26, R. Suleiman13,19, J. Templon6, T. Teresawa31, J. Thompson34, R. Tieulent17, L. Todor23, B. T. Tonguc29, P. E. Ulmer23, G. M. Urciuoli11, B. Vlahovic21, K. Wijesooriya34, R. Wilson8, B. Wojtsekhowski12, R. Woo32, W. Xu19, I. Younus29, and C. Zhang17 (HAPPEX Collaboration)
1California State University, Los Angeles, Los Angeles, California 90032, USA
2Université Blaise Pascal∕IN2P3, F-63177 Aubière, France
3Eastern Kentucky University, Richmond, Kentucky 40475, USA
4Florida International University, Miami, Florida 33199, USA
5Université Joseph Fourier, F-38041 Grenoble, France
6University of Georgia, Athens, Georgia 30602, USA
7Hampton University, Hampton, Virginia 23668, USA
8Harvard University, Cambridge, Massachusetts 02138, USA
9INFN, Sezione di Bari and University of Bari, I-70126 Bari, Italy
10INFN, Sezione di Roma III, 00146 Roma, Italy
11INFN, Sezione Sanità, 00161 Roma, Italy
12Thomas Jefferson National Accelerator Laboratory, Newport News, Virginia 23606, USA
13Kent State University, Kent, Ohio 44242, USA
14University of Kentucky, Lexington, Kentucky 40506, USA
15Kharkov Institute of Physics and Technology, Kharkov 310108, Ukraine
16Kyungpook National University, Taegu 702-701, Korea
17University of Maryland, College Park, Maryland 20742, USA
18University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA
19Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
20University of New Hampshire, Durham, New Hampshire 03824, USA
22Norfolk State University, Norfolk, Virginia 23504, USA
21North Carolina Central University, Durham, North Carolina 27707, USA
23Old Dominion University, Norfolk, Virginia 23508, USA
24Princeton University, Princeton, New Jersey 08544, USA
25University of Regina, Regina, Saskatchewan, S4S 0A2 Canada
26Rutgers, The State University of New Jersey, Piscataway, New Jersey 08855, USA
27CEA Saclay, DAPNIA∕SPhN, F-91191 Gif-sur-Yvette, France
28State University of New York at Stony Brook, Stony Brook, New York 11794, USA
29Syracuse University, Syracuse, New York 13244, USA
30Temple University, Philadelphia, Pennsylvania 19122, USA
31Tohoku University, Sendai 9890, Japan
32TRIUMF, Vancouver, British Columbia, V6T 2A3 Canada
33University of Virginia, Charlottesville, Virginia 22901, USA
34College of William and Mary, Williamsburg, Virginia 23187, USA
Received 16 January 2004; published 15 June 2004
We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is A=−15.05±0.98(stat)±0.56(syst) ppm at the kinematic point ⟨θlab⟩=12.3° and ⟨Q2⟩=0.477 (GeV∕c)2. Based on these data as well as data on electromagnetic form factors, we extract the linear combination of strange form factors GEs+0.392GMs=0.014±0.020±0.010, where the first error arises from this experiment and the second arises from the electromagnetic form factor data. This paper provides a full description of the special experimental techniques employed for precisely measuring the small asymmetry, including the first use of a strained GaAs crystal and a laser-Compton polarimeter in a fixed target parity-violation experiment.
© 2004 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevC.69.065501
DOI:
10.1103/PhysRevC.69.065501
PACS:
13.60.Fz, 11.30.Er, 13.40.Gp, 14.20.Dh
*Electronic address: finn@physics.wm.edu †Present address: Duke University, Durham, North Carolina 27708, USA. ‡Present address: University of Chicago, Chicago IL 60637, USA. §Electronic address: souder@phy.syr.edu
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