Measurement of the beam-spin azimuthal asymmetry associated with deeply-virtual Compton scattering -: art. no. 182001

被引：331

作者：

Airapetian, A

Akopov, N

Akopov, Z

Amarian, M

Achenauer, EC

Avakian, H

Avakian, R

Avetissian, A

Avetissian, E

Bailey, P

Bains, B

Baturin, V

Baumgarten, C

Beckmann, M

Belostotski, S

Bernreuther, S

Bianchi, N

Böttcher, H

Borissov, A

Bouhali, O

Bouwhuis, M

Brack, J

Brauksiepe, S

Brückner, W

Brüll, A

Brunn, I

Bulten, HJ

Capitani, GP

Chumney, P

Cisbani, E

Ciullo, G

Court, GR

Dalpiaz, PF

De Leo, R

De Nardo, L

De Sanctis, E

De Schepper, D

Devitsin, E

Huberts, PKAD

Di Nezza, P

Düren, M

Ehrenfried, M

Elbakian, G

Ellinghaus, F

Ely, J

Fabbri, R

Fantoni, A

Fechtchenko, A

Felawka, L

Filippone, BW

机构：

[1] Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada

[2] Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA

[3] Ist Nazl Fis Nucl, Sez Bari, I-70124 Bari, Italy

[4] CALTECH, WK Kellogg Radiat Lab, Pasadena, CA 91125 USA

[5] Univ Colorado, Nucl Phys Lab, Boulder, CO 80309 USA

[6] DESY, D-22603 Hamburg, Germany

[7] DESY, D-15738 Zeuthen, Germany

[8] Joint Inst Nucl Res, Dubna 141980, Russia

[9] Univ Erlangen Nurnberg, Inst Phys, D-91058 Erlangen, Germany

[10] Ist Nazl Fis Nucl, Sez Ferrara, I-44100 Ferrara, Italy

[11] Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy

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

[13] Univ Freiburg, Fak Phys, D-79104 Freiburg, Germany

[14] Univ Ghent, Dept Subatom & Radiat Phys, B-9000 Ghent, Belgium

[15] Max Planck Inst Kernphys, D-69029 Heidelberg, Germany

[16] Univ Illinois, Dept Phys, Urbana, IL 61801 USA

[17] Univ Liverpool, Dept Phys, Liverpool L69 7ZE, Merseyside, England

[18] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA

[19] MIT, Nucl Sci Lab, Cambridge, MA 02139 USA

[20] Univ Michigan, Randall Lab Phys, Ann Arbor, MI 48109 USA

[21] PN Lebedev Phys Inst, Moscow 117924, Russia

[22] Univ Munich, Sekt Phys, D-85748 Garching, Germany

[23] New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA

[24] NIKHEF, Natl Inst Kernfys & Hoge Energiefys, NL-1009 DB Amsterdam, Netherlands

[25] Petersburg Nucl Phys Inst, Gatchina 188350, Russia

[26] Univ Regensburg, Inst Theoret Phys, D-93040 Regensburg, Germany

[27] Ist Nazl Fis Nucl, Sez Rome 1, Grp Sanita, I-00161 Rome, Italy

[28] Ist Super Sanita, Phys Lab, I-00161 Rome, Italy

[29] Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada

[30] TRIUMF, Vancouver, BC V6T 2A3, Canada

[31] Tokyo Inst Technol, Dept Phys, Tokyo 152, Japan

[32] Vrije Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands

来源：

PHYSICAL REVIEW LETTERS | 2001年 / 87卷 / 18期

关键词：

D O I：

10.1103/PhysRevLett.87.182001

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The beam-spin asymmetry in hard electroproduction of photons has been measured. The data have been accumulated by the HERMES experiment at DESY using the HERA 27.6 GeV longitudinally polarized positron beam and an unpolarized hydrogen-gas target. The asymmetry in the azimuthal distribution of the produced photons in the angle phi relative to the lepton scattering plane was determined with respect to the helicity state of the incoming positron beam. The beam-spin analyzing power in the sin phi moment was measured to be -0.23 +/- 0.04(stat) +/- 0.03(syst) in the missing-mass range below 1.7 GeV. The observed asymmetry is attributed to the interference of the Bethe-Heitler and deeply virtual Compton scattering processes.

引用

页码：182001 / 182001

页数：5

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