Measurement of ep→epπ0 beam spin asymmetries above the resonance region

被引：43

作者：

De Masi, R. ^{[1
]}

Garcon, M. ^{[1
]}

Zhao, B. ^{[2
]}

Amaryan, M. J. ^{[28
]}

Ambrozewicz, P. ^{[11
]}

Anghinolfi, M. ^{[17
]}

Asryan, G. ^{[39
]}

Avakian, H. ^{[34
]}

Bagdasaryan, H. ^{[28
]}

Baillie, N. ^{[38
]}

Ball, J. ^{[1
]}

Ball, J. P. ^{[4
]}

Baltzell, N. A. ^{[33
]}

Batourine, V. ^{[22
]}

Battaglieri, M. ^{[17
]}

Bedlinskiy, I. ^{[18
]}

Bellis, M. ^{[7
]}

Benmouna, N. ^{[13
]}

Berman, B. L. ^{[13
]}

Bertin, P.

Biselli, A. S. ^{[10
]}

Blaszczyk, L. ^{[12
]}

Bouchigny, S. ^{[29
]}

Boiarinov, S. ^{[34
]}

Bradford, R. ^{[7
]}

Branford, D. ^{[9
]}

Briscoe, W. J. ^{[13
]}

Brooks, W. K. ^{[34
]}

Bultmann, S. ^{[28
]}

Burkert, V. D. ^{[34
]}

Butuceanu, C. ^{[38
]}

Calarco, J. R. ^{[25
]}

Careccia, S. L. ^{[28
]}

Carman, D. S. ^{[34
]}

Casey, L. ^{[8
]}

Chen, S. ^{[12
]}

Cheng, L. ^{[8
]}

Cole, P. L. ^{[15
]}

Collins, P.

Coltharp, P. ^{[12
]}

Crabb, D. ^{[37
]}

Crede, V. ^{[12
]}

Dashyan, N. ^{[39
]}

De Sanctis, E. ^{[16
]}

De Vita, R. ^{[17
]}

Degtyarenko, P. V. ^{[34
]}

Deur, A. ^{[34
]}

Dharmawardane, K. V. ^{[28
]}

Dickson, R. ^{[7
]}

Djalali, C. ^{[33
]}

机构：

[1] CEA Saclay, Serv Phys Nucl, F-91191 Gif Sur Yvette, France

[2] Univ Connecticut, Storrs, CT 06269 USA

[3] Argonne Natl Lab, Argonne, IL 60439 USA

[4] Arizona State Univ, Tempe, AZ 85287 USA

[5] Univ Calif Los Angeles, Los Angeles, CA 90095 USA

[6] Calif State Univ Dominguez Hills, Carson, CA 90747 USA

[7] Carnegie Mellon Univ, Pittsburgh, PA 15213 USA

[8] Catholic Univ Amer, Washington, DC 20064 USA

[9] Univ Edinburgh, Edinburgh EH9 3JZ, Midlothian, Scotland

[10] Fairfield Univ, Fairfield, CT 06824 USA

[11] Florida Int Univ, Miami, FL 33199 USA

[12] Florida State Univ, Tallahassee, FL 32306 USA

[13] George Washington Univ, Washington, DC 20052 USA

[14] Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland

[15] Idaho State Univ, Pocatello, ID 83209 USA

[16] Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy

[17] Ist Nazl Fis Nucl, Sez Genova, I-16146 Genoa, Italy

[18] Inst Theoret & Expt Phys, RU-117259 Moscow, Russia

[19] Univ Blaise Pascal, LPC Clermont Ferrand, CNRS, IN2P3, F-63177 Aubiere, France

[20] Univ Grenoble 1, CNRS, IN2P3, LPSC,INPG, F-38026 Grenoble, France

[21] James Madison Univ, Harrisonburg, VA 22807 USA

[22] Kyungpook Natl Univ, Taegu 702701, South Korea

[23] Univ Massachusetts, Amherst, MA 01003 USA

[24] Moscow MV Lomonosov State Univ, Gen Nucl Phys Inst, RU-119899 Moscow, Russia

[25] Univ New Hampshire, Durham, NH 03824 USA

[26] Norfolk State Univ, Norfolk, VA 23504 USA

[27] Ohio Univ, Athens, OH 45701 USA

[28] Old Dominion Univ, Norfolk, VA 23529 USA

[29] Inst Phys Nucl, F-91406 Orsay, France

[30] Rensselaer Polytech Inst, Troy, NY 12180 USA

[31] Rice Univ, Houston, TX 77005 USA

[32] Univ Richmond, Richmond, VA 23173 USA

[33] Univ S Carolina, Columbia, SC 29208 USA

[34] Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA

[35] Union Coll, Schenectady, NY 12308 USA

[36] Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA

[37] Univ Virginia, Charlottesville, VA 22901 USA

[38] Coll William & Mary, Williamsburg, VA 23187 USA

[39] Yerevan Phys Inst, Yerevan 375036, Armenia

来源：

PHYSICAL REVIEW C | 2008年 / 77卷 / 04期

基金：

英国科学技术设施理事会;

关键词：

D O I：

10.1103/PhysRevC.77.042201

中图分类号：

O57 [原子核物理学、高能物理学];

学科分类号：

070202 ;

摘要：

The beam spin asymmetry (BSA) in the exclusive reaction ep -> ep pi(0) was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The x(B),Q(2),t, and phi dependences of the pi(0) BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sin phi function and their amplitudes are extracted. Overall, they are of the order of 0.04-0.11 and roughly independent of t. This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as the extension of a Regge formalism at high photon virtualities, are discussed.

引用

页数：5

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