@article{6f8f8ef13885491ab0fcbf6afaa69fb3,
title = "Measurement of the spin asymmetry in the photoproduction of pairs of high-pT hadrons at HERMES",
abstract = "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 pairs with ph1 T>1.5GeV/c and ph2 T>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.",
author = "{HERMES Collaboration} and A. Airapetian and N. Akopov and M. Amarian and Aschenauer, {E. C.} and H. Avakian and R. Avakian and A. Avetissian and B. Bains and C. Baumgarten and M. Beckmann and S. Belostotski and Belz, {J. E.} and Th Benisch and S. Bernreuther and N. Bianchi and J. Blouw and H. B{\"o}ttcher and A. Borissov and J. Brack and S. Brauksiepe and B. Braun and W. Br{\"u}ckner and A. Br{\"u}ll and Bulten, {H. J.} and Capitani, {G. P.} and P. Carter and P. Chumney and E. Cisbani and Court, {G. R.} and Dalpiaz, {P. F.} and {De Sanctis}, E. and {De Schepper}, D. and E. Devitsin and {de Witt-Huberts}, {N. K.A.} and {Di Nezza}, P. and M. D{\"u}ren and A. Dvoredsky and G. Elbakian and J. Ely and A. Fantoni and M. Ferstl and K. Fiedler and Filippone, {B. W.} and H. Fischer and B. Fox and J. Franz and S. Frullani and Funk, {M. A.} and Y. G{\"a}rber and Y. Sakemi",
year = "2000",
doi = "10.1103/PhysRevLett.84.2584",
language = "English",
volume = "84",
pages = "2584--2588",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "12",
}