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Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High- pT Hadrons at HERMES

Airapetian, A. and Akopov, N. and Amarian, M. and Aschenauer, E. C. and Avakian, H. and Avakian, R. and Avetissian, A. and Bains, B. and Baumgarten, C. and Beckmann, M. and Belostotski, S. and Belz, J. E. and Benisch, Th. and Bernreuther, S. and Bianchi, N. and Blouw, J. and Böttcher, H. and Borissov, A. and Brack, J. and Brauksiepe, S. and Braun, B. and Brückner, W. and Brüll, A. and Bulten, H. J. and Capitani, G. P. and Carter, P. and Chumney, P. and Cisbani, E. and Court, G. R. and Dalpiaz, P. F. and De-Sanctis, E. and De-Schepper, D. and Devitsin, E. and de-Witt-Huberts, P. K. A. and Di-Nezza, P. and Düren, M. and Dvoredsky, A. and Elbakian, G. and Ely, J. and Fantoni, A. and Ferstl, M. and Fiedler, K. and Filippone, B. W. and Fischer, H. and Fox, B. and Franz, J. and Frullani, S. and Funk, M.-A. and Gärber, Y. and Garibaldi, F. and Gavrilov, G. and Geiger, P. and Gharibyan, V. and Golendukhin, A. and Graw, G. and Grebeniouk, O. and Green, P. W. and Greeniaus, L. G. and Grosshauser, C. and Guidal, M. and Gute, A. and Haeberli, W. and Hansen, J.-O. and Hasch, D. and Häusser, O. and Heinsius, F. H. and Henderson, R. and Henoch, M. and Hertenberger, R. and Holler, Y. and Holt, R. J. and Hoprich, W. and Ihssen, H. and Iodice, M. and Izotov, A. and Jackson, H. E. and Jgoun, A. and Kaiser, R. and Kinney, E. and Kisselev, A. and Kitching, P. and Kobayashi, H. and Koch, N. and Königsmann, K. and Kolstein, M. and Kolster, H. and Korotkov, V. and Korsch, W. and Kozlov, V. and Kramer, L. H. and Kurisuno, M. and Kyle, G. and Lachnit, W. and Lorenzon, W. and Makins, N. C. R. and Martens, F. K. and Martin, J. W. and Masoli, F. and Mateos, A. and McAndrew, M. and McIlhany, K. and McKeown, R. D. and Meissner, F. and Menden, F. M. and Metz, A. and Meyners, N. and Mikloukho, O. and Miller, C. A. and Miller, M. A. and Milner, R. and Most, A. and Muccifora, V. and Naryshkin, Y. and Nathan, A. M. and Neunreither, F. and Niczyporuk, M. and Nowak, W.-D. and O'Neill, T. G. and Openshaw, R. and Ouyang, J. and Owen, B. R. and Pate, S. F. and Potashov, S. and Potterveld, D. H. and Rakness, G. and Redwine, R. and Reolon, A. R. and Ristinen, R. and Rith, K. and Rossi, P. and Rudnitsky, S. and Ruh, M. and Ryckbosch, D. and Sakemi, Y. and Scarlett, C. and Schäfer, A. and Schmidt, F. and Schmitt, H. and Schnell, G. and Schüler, K. P. and Schwind, A. and Seibert, J. and Shibata, T.-A. and Shibatani, K. and Shin, T. and Shutov, V. and Simani, C. and Simon, A. and Sinram, K. and Slavich, P. and Spengos, M. and Steffens, E. and Stenger, J. and Stewart, J. and Stoesslein, U. and Sutter, M. and Tallini, H. and Taroian, S. and Terkulov, A. and Tipton, B. and Tytgat, M. and Uriuoli, G. M. and van-de-Vyver, R. and van-den-Brand, J. F. J. and van-der-Steenhoven, G. and van-Hunen, J. J. and Vetterli, M. C. and Vikhrov, V. and Vincter, M. G. and Visser, J. and Volk, E. and Wander, W. and Wendland, J. and Williamson, S. E. and Wise, T. and Woller, K. and Yoneyama, S. and Zohrabian, H. (2000) Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High- pT Hadrons at HERMES. Physical Review Letters, 84 (12). pp. 2584-2588. ISSN 0031-9007. doi:10.1103/PhysRevLett.84.2584.

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We present a measurement of the longitudinal spin asymmetry A|| in photoproduction of pairs of hadrons with high transverse momentum pT. 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 _(pT)^(h1)>1.5GeV/c and _(pT)^(h2)>1.0GeV/c, the measured asymmetry is A_(||) = -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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Cisbani, E.0000-0002-6774-8473
Filippone, B. W.0000-0002-2618-2688
Miller, M. A.0000-0002-3964-9312
Wise, T.0000-0002-9021-3282
Additional Information:© 2000 The American Physical Society. Received 15 July 1999. We gratefully acknowledge the DESY management for its support, the DESY staff and the staffs of the collaborating institutions for their significant effort, and our funding agencies for financial support.
Funding AgencyGrant Number
Deutsches Elektronen-SynchrotronUNSPECIFIED
Issue or Number:12
Classification Code: PACS: 14.20.Dh, 13.60.Hb, 13.88.+e, 25.20.Lj
Record Number:CaltechAUTHORS:20100113-081941610
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:17154
Deposited By: Ruth Sustaita
Deposited On:26 Jan 2010 21:36
Last Modified:08 Nov 2021 23:33

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