Measurement of the spin asymmetry in the photoproduction of pairs of high-pT hadrons at HERMES

被引：191

作者：

Airapetian, A ^{[1
]}

Akopov, N

Amarian, M

Aschenauer, EC

Avakian, H

Avakian, R

Avetissian, A

Bains, B

Baumgarten, C

Beckmann, M

Belostotski, S

Belz, JE

Benisch, T

Bernreuther, S

Bianchi, N

Blouw, J

Böttcher, H

Borissov, A

Brack, J

Brauksiepe, S

Braun, B

Brückner, W

Brüll, A

Bulten, HJ

Capitani, GP

Carter, P

Chumney, P

Cisbani, E

Court, GR

Dalpiaz, PF

De Sanctis, E

De Schepper, D

Devitsin, E

Huberts, PKAD

Di Nezza, P

Düren, M

Dvoredsky, A

Elbakian, G

Ely, J

Fantoni, A

Ferstl, M

Fiedler, K

Filippone, BW

Fischer, H

Fox, B

Franz, J

Frullani, S

Funk, MA

Gärber, Y

Garibaldi, F

机构：

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

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

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

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

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

[6] DESY, Deutsch Elekt Synchrotron, 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] Univ Ferrara, Dipartimento Fis, I-44100 Ferrara, Italy

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

[12] Florida Int Univ, Dept Phys, Miami, FL 33199 USA

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

[14] Univ Ghent, Dept Subat & 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 Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA

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

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

[20] Univ Marburg, Inst Phys, D-35037 Marburg, Germany

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

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

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

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

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

[26] NIKHEF, NL-1009 DB Amsterdam, Netherlands

[27] Petersburg Nucl Phys Inst, St Petersburg 188350, Russia

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

[29] Ist Nazl Fis Nucl, Sez Sanita, I-00161 Rome, Italy

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

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

[32] Tokyo Inst Technol, Tokyo 152, Japan

[33] Free Univ Amsterdam, Dept Phys & Astron, NL-1081 HV Amsterdam, Netherlands

[34] Yerevan Phys Inst, Yerevan 375036, Armenia

来源：

PHYSICAL REVIEW LETTERS | 2000年 / 84卷 / 12期

关键词：

D O I：

10.1103/PhysRevLett.84.2584

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We present a measurement of the longitudinal spin asymmetry Ali in photoproduction of pairs of hadrons with high transverse momentum pi. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h(+)h(-) pairs with p(T)(h1) > 1.5 GeV/c and p(T)(h2) > 1.0 GeV/c, the measured asymmetry is A(parallel to) = -0.28 +/- 0.12(stat) +/- 0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering: from protons, and is interpreted to arise from a positive gluon polarization.

引用

页码：2584 / 2588

页数：5

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