Phys. Rev. Lett.
100,
162002
(2008)
[6 pages]
Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries
F. X. Girod et al. CLAS Collaboration
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F. X. Girod1,2, R. A. Niyazov2,32, H. Avakian2, J. Ball1, I. Bedlinskiy3, V. D. Burkert2, R. De Masi1,4, L. Elouadrhiri2, M. Garçon1,*, M. Guidal4, H. S. Jo4, K. Joo12, V. Kubarovsky2,32, S. V. Kuleshov3, M. MacCormick4, S. Niccolai4, O. Pogorelko3, F. Sabatié1, S. Stepanyan2, P. Stoler32, M. Ungaro12, B. Zhao12, M. J. Amaryan31, P. Ambrozewicz15, M. Anghinolfi21, G. Asryan40, H. Bagdasaryan31, N. Baillie29, J. P. Ball6, N. A. Baltzell35, V. Batourine23, M. Battaglieri21, M. Bellis9, N. Benmouna17, B. L. Berman17, A. S. Biselli9,14, L. Blaszczyk16, S. Bouchigny4, S. Boiarinov2, R. Bradford9, D. Branford13, W. J. Briscoe17, W. K. Brooks2, S. Bültmann31, C. Butuceanu39, J. R. Calarco28, S. L. Careccia31, D. S. Carman2, L. Casey10, S. Chen16, L. Cheng10, P. L. Cole19, P. Collins6, P. Coltharp16, D. Crabb38, V. Crede16, N. Dashyan40, E. De Sanctis20, R. De Vita21, P. V. Degtyarenko2, A. Deur2, K. V. Dharmawardane31, R. Dickson9, C. Djalali35, G. E. Dodge31, J. Donnelly18, D. Doughty11,12, M. Dugger6, O. P. Dzyubak35, H. Egiyan2, K. S. Egiyan40, L. El Fassi5, P. Eugenio16, G. Fedotov27, G. Feldman17, H. Funsten39, G. Gavalian31, G. P. Gilfoyle34, K. L. Giovanetti22, J. T. Goetz7, A. Gonenc15, R. W. Gothe35, K. A. Griffioen39, N. Guler31, L. Guo2, V. Gyurjyan2, K. Hafidi5, H. Hakobyan40, C. Hanretty16, F. W. Hersman28, K. Hicks30, I. Hleiqawi30, M. Holtrop28, C. E. Hyde24,31, Y. Ilieva17, D. G. Ireland18, B. S. Ishkhanov27, E. L. Isupov27, M. M. Ito2, D. Jenkins37, J. R. Johnstone18, H. G. Juengst17,31, N. Kalantarians31, J. D. Kellie18, M. Khandaker29, W. Kim23, A. Klein31, F. J. Klein10, A. V. Klimenko31, M. Kossov3, Z. Krahn9, L. H. Kramer15,2, J. Kuhn9, S. E. Kuhn31, J. Lachniet9,31, J. M. Laget2, J. Langheinrich35, D. Lawrence26, T. Lee28, K. Livingston18, H. Y. Lu35, N. Markov12, P. Mattione33, M. Mazouz25, B. McKinnon18, B. A. Mecking2, M. D. Mestayer2, C. A. Meyer9, T. Mibe30, B. Michel24, K. Mikhailov3, M. Mirazita20, R. Miskimen26, V. Mokeev27,2, K. Moriya9, S. A. Morrow1,4, M. Moteabbed15, E. Munevar17, G. S. Mutchler33, P. Nadel-Turonski17, R. Nasseripour15,35, G. Niculescu22, I. Niculescu22, B. B. Niczyporuk2, M. R. Niroula31, M. Nozar2, M. Osipenko21,27, A. I. Ostrovidov16, K. Park35, E. Pasyuk6, C. Paterson18, S. Anefalos Pereira20, J. Pierce38, N. Pivnyuk3, D. Pocanic38, S. Pozdniakov3, J. W. Price8, S. Procureur1, Y. Prok38,2, D. Protopopescu18, B. A. Raue15,2, G. Ricco21, M. Ripani21, B. G. Ritchie6, G. Rosner18, P. Rossi20, J. Salamanca19, C. Salgado20, J. P. Santoro10, V. Sapunenko2, R. A. Schumacher9, V. S. Serov3, Y. G. Sharabian2, D. Sharov27, N. V. Shvedunov27, E. S. Smith2, L. C. Smith38, D. I. Sober10, D. Sokhan13, A. Stavinsky3, S. S. Stepanyan23, B. E. Stokes16, I. I. Strakovsky17, S. Strauch17,35, M. Taiuti21, D. J. Tedeschi35, A. Tkabladze30,17, S. Tkachenko31, C. Tur35, M. F. Vineyard36, A. V. Vlassov3, E. Voutier25, D. P. Watts18, L. B. Weinstein31, D. P. Weygand2, M. Williams9, E. Wolin2, M. H. Wood35, A. Yegneswaran2, L. Zana28, J. Zhang31, and Z. W. Zhao35 (CLAS Collaboration)
1CEA-Saclay, Service de Physique Nucléaire, 91191 Gif-sur-Yvette, France
2Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA
3Institute of Theoretical and Experimental Physics, Moscow, 117259, Russia
4IPNO, Université Paris-Sud, CNRS/IN2P3, 91406 Orsay, France
5Argonne National Laboratory, Argonne, Illinois 60439, USA
6Arizona State University, Tempe, Arizona 85287-1504, USA
7University of California at Los Angeles, Los Angeles, California 90095-1547, USA
8California State University, Dominguez Hills, Carson, California 90747, USA
9Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
10Catholic University of America, Washington, D.C. 20064, USA
11Christopher Newport University, Newport News, Virginia 23606, USA
12University of Connecticut, Storrs, Connecticut 06269, USA
13Edinburgh University, Edinburgh EH9 3JZ, United Kingdom
14Fairfield University, Fairfield Connecticut 06824, USA
15Florida International University, Miami, Florida 33199, USA
16Florida State University, Tallahassee, Florida 32306, USA
17The George Washington University, Washington, D.C. 20052, USA
18University of Glasgow, Glasgow G12 8QQ, United Kingdom
19Idaho State University, Pocatello, Idaho 83209, USA
20INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy
21INFN, Sezione di Genova, 16146 Genova, Italy
22James Madison University, Harrisonburg, Virginia 22807, USA
23Kyungpook National University, Daegu 702-701, South Korea
24LPC Clermont-Ferrand, Université Blaise Pascal, CNRS-IN2P3, 63177 Aubière, France
25LPSC, Université Joseph Fourier, CNRS/IN2P3, INPG, 38026 Grenoble, France
26University of Massachusetts, Amherst, Massachusetts 01003, USA
27Moscow State University, General Nuclear Physics Institute, 119899 Moscow, Russia
28University of New Hampshire, Durham, New Hampshire 03824-3568, USA
29Norfolk State University, Norfolk, Virginia 23504, USA
30Ohio University, Athens, Ohio 45701, USA
31Old Dominion University, Norfolk, Virginia 23529, USA
32Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA
33Rice University, Houston, Texas 77005-1892, USA
34University of Richmond, Richmond, Virginia 23173, USA
35University of South Carolina, Columbia, South Carolina 29208, USA
36Union College, Schenectady, New York 12308, USA
37Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0435, USA
38University of Virginia, Charlottesville, Virginia 22901, USA
39College of William and Mary, Williamsburg, Virginia 23187-8795, USA
40Yerevan Physics Institute, 375036 Yerevan, Armenia
Received 6 December 2007; published 23 April 2008
The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (e⃗p→epγ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering. Over the whole kinematic range (xB from 0.11 to 0.58, Q2 from 1 to 4.8 GeV2, -t from 0.09 to 1.8 GeV2), the azimuthal dependence of the asymmetries is compatible with expectations from leading-twist dominance, A≃asinϕ/(1+ccosϕ). This extensive set of data can thus be used to constrain significantly the generalized parton distributions of the nucleon in the valence quark sector.
© 2008 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.100.162002
DOI:
10.1103/PhysRevLett.100.162002
PACS:
13.60.Fz, 13.40.Gp, 13.60.Hb, 14.20.Dh
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