1. Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
- Author
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R. Sulej, S. Neliba, P. Berglund, B. Grube, M.G. Sapozhnikov, H. Schmitt, A. Maggiora, E. Rondio, M. Varanda, A. Zvyagin, W. Kastaun, Colin Bernet, A. Srnka, I. Konorov, M.P. Bussa, A. Korzenev, E.S. Ageev, F. H. Heinsius, S. Gerassimov, J. M. Le Goff, T. Toeda, Marc Wagner, P.D. Eversheim, A. Mielech, S. Ishimoto, Frank Klein, K. Kondo, K. Zaremba, M. Wiesmann, J. Reymann, A.A. Shishkin, V. Duic, Sergey Donskov, O.P. Gavrichtchouk, S. Platchkov, P. Rebourgeard, Y. Bedfer, N. Dedek, L. Sinha, F. Balestra, S. Paul, R. Ziegler, V.N. Kolosov, V.A. Polyakov, N.P. Kravchuk, A.K. Konoplyannikov, J. Zhao, R. Jahn, A. Gorin, V. Diaz, M. Maggiora, R. Ijaduola, N. Takabayashi, R. De Masi, P. Bordalo, J. Bisplinghoff, Massimo Lamanna, Yu. Kisselev, A. Amoroso, Vladimir Peshekhonov, R. Birsa, E.V. Komissarov, Andres Cicuttin, J. Lichtenstadt, Norihiro Doshita, G. Piragino, N. d'Hose, Yu.A. Khokhlov, A. Maximov, G. Reicherz, Josef Pochodzalla, I. Ludwig, Naoaki Horikawa, M. Ostrick, Aram Kotzinian, R. Windmolders, A.A. Nozdrin, J. Nassalski, M. Giorgi, R. Bertini, Andrea Ferrero, Oleg V. Ivanov, R. Joosten, S. Dalla Torre, A. N. Sissakian, J.M. Friedrich, V.D. Samoylenko, Yu. Alexandrov, P. Fauland, Christian Schill, C. Marchand, M.E. Ladygin, V.F. Obraztsov, M. Finger, E. Weise, L. Ferrero, D. Kang, M.L. Colantoni, K. Königsmann, S. Hedicke, A. Colavita, S. Horikawa, R. C. Webb, A.M. Dinkelbach, K. Platzer, V.N. Bytchkov, A.V. Dolgopolov, S. Procureur, K. Kowalik, A.B. Sadovski, L. Cerini, V.I. Tretyak, J. Pretz, A. Grünemaier, G.V. Krivokhizhin, O.A. Grajek, N.A. Koutchinski, M. von Hodenberg, A. Sandacz, F. Karstens, U. Wiedner, S. S. Dasgupta, G.V. Khaustov, L. Schmitt, A. Grasso, M. Stolarski, J. Franz, L. G. Tkatchev, F. Stinzing, Grzegorz Brona, Miroslav Sulc, D. Thers, Anna Zanetti, A. Janata, Franco Bradamante, Gerhard K. Mallot, J. Ehlers, F. Kunne, V.V. Tchalishev, N.I. Jouravlev, S. Costa, E. Burtin, V.F. Konstantinov, W. Meyer, Maria Liz Crespo, A.I. Ioukaev, F. Sozzi, R. Hermann, E. M. Kabuß, Paolo Pagano, V.P. Sugonyaev, Q. Weitzel, A.A. Popov, S. Ramos, J.H. Koivuniemi, K. Rith, F. Hinterberger, P. Schiavon, S. Panebianco, H. Fischer, K. Medved, Alan D. Martin, Z.V. Kroumchtein, W. Eyrich, T. Hasegawa, A. Chapiro, Murray Moinester, T. Schmidt, D. Neyret, M. A. Faessler, Alessandro Bressan, D. von Harrach, C. Ilgner, Yu.V. Mikhailov, S. Trousov, J. Marzec, R. Geyer, A.G. Olshevsky, St. Goertz, O.Yu. Denisov, C. Heß, A. Magnon, L. Dhara, M. Slunecka, Takahiro Iwata, E. Saller, S. Koblitz, M. Sans, B. Gobbo, B. Badelek, J. Marroncle, A. Teufel, Miroslav Virius, K. Kurek, A. Padee, B. Ketzer, D. Peshekhonov, W. Wiślicki, H. D. Pereira, N.V. Vlassov, S. Wirth, C. Quintans, J. Hannappel, Günter Baum, O.Yu. Shevchenko, I.A. Savin, A. Bravar, V.I. Nikolaenko, R. Garfagnini, H.-W. Siebert, I. Manuilov, V. Falaleev, D. Panzieri, T. Liška, M. Fabro, M. Leberig, A.M. Rozhdestvensky, N. V. Khomutov, J. Ball, G.I. Smirnov, Fabrice Gautheron, T. Matsuda, V. Frolov, V.Yu. Alexakhin, W. Dünnweber, G. D. Alexeev, V.A. Dorofeev, A.S. Korentchenko, F. Tessarotto, R. Kuhn, O. Nähle, V. Kalinnikov, and A. Skachkova
- Subjects
Quantum chromodynamics ,Physics ,Nuclear and High Energy Physics ,Particle physics ,Muon ,010308 nuclear & particles physics ,Hadron ,Deep inelastic scattering ,01 natural sciences ,Helicity ,Gluon ,Nuclear physics ,0103 physical sciences ,COMPASS experiment ,High Energy Physics::Experiment ,Nuclear Experiment ,010306 general physics ,Nucleon - Abstract
We present a determination of the gluon polarization Δ G / G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q 2 1 ( GeV / c ) 2 , with a pair of large transverse-momentum hadrons in the final state. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a polarized 6 LiD target. The helicity asymmetry for the selected events is 〈 A ∥ / D 〉 = 0.002 ± 0.019 ( stat ) ± 0.003 ( syst ) . From this value, we obtain in a leading-order QCD analysis Δ G / G = 0.024 ± 0.089 ( stat ) ± 0.057 ( syst ) at x g = 0.095 and μ 2 ≃ 3 ( GeV / c ) 2 .
- Published
- 2006
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