Gluon polarization in the nucleon from quasi-real photoproduction of high-p hadron pairs

Ageev, E. S.; Alexakhin V., Yu; Alexandrov, Yu; Alexeev, G. D.; Amoroso, A; Badelek, B; Balestra, E. S.; Alexakhin V., Yu; Alexandrov, Yu; Alexeev, G. D.; Amoroso, A; Badelek, B; Balestra, F; Ball, J; Baum, G; Bedfer, Y; Berglund, P; Bernet, C; Bertini, R; Birsa, R; Bisplinghoff, J; Bordalo, P; Bradamante, Franco; Bravar, A; Bressan, Andrea; Brona, G; Burtin, E; Bussa, M. P.; Bytchkov, V. N.; Cerini, L; Chapiro, A; Cicuttin, A; Colantoni, M; Colavita, A. A.; Costa, S; Crespo, M. L.; Dalla Torre, S; Dasgupta, S. S.; Dedek, N; De Masi, R; Denisov O., Yu; Dhara, L; Diaz, V; Dinkelbach, A. M.; Dolgopolov, A. V.; Donskov, S. V.; Dorofeev, V. A.; Doshita, N; Duic, Venicio; Dünnweber, W; Ehlers, J; Eversheim, P. D.; Eyrich, W; Fabro, M; Faessler, M; Falaleev, V; Fauland, P; Ferrero, A; Ferrero, L; Finger, M; Finger M., Jr; Fischer, H; Franz, J; Friedrich, J. M.; Frolov, V; Garfagnini, R; Gautheron, F; Gavrichtchouk, O. P.; Gerassimov, S; Geyer, R; Giorgi, Marcello; Gobbo, B; Goertz, S; Gorin, A. M.; Grajek, O. A.; Grasso, A; Grube, B; Grünemaier, A; Hannappel, J; Von Harrach, D; Hasegawa, T; Hedicke, S; Heinsius, F. H.; Hermann, R; Hess, C; Hinterberger, F; Von Hodenberg, M; Horikawa, N; Horikawa, S; D'Hose, N; Ijaduola, R. B.; Ilgner, C; Ioukaev, A. I.; Ishimoto, S; Ivanov, O; Iwata, T; Jahn, R; Janata, A; Joosten, R; Jouravlev, N. I.; Kabuss, E; Kalinnikov, V; Kang, D; Karstens, F; Kastaun, W; Ketzer, B; Khaustov, G. V.; Khokhlov, Y. U. A.; Khomutov, N. V.; Kisselev, Yu; Klein, F; Koblitz, S; Koivuniemi, J. H.; Kolosov, V. N.; Komissarov, E. V.; Kondo, K; Königsmann, K; Konoplyannikov, A. K.; Konorov, I; Konstantinov, V. F.; Korentchenko, A. S.; Korzenev, A; Kotzinian, A. M.; Koutchinski, N. A.; Kowalik, K; Kravchuk, N. P.; Krivokhizhin, G. V.; Kroumchtein, Z. V.; Kuhn, R; Kunne, F; Kurek, K; Ladygin, M. E.; Lamanna, M; Leberig, M; Le Goff, J. M.; Lichtenstadt, J; Liska, T; Ludwig, I; Maggiora, A; Maggiora, M; Magnon, A; Mallot, G. K.; Manuilov, I. V.; Marchand, C; Marroncle, J; Martin, Anna; Marzec, J; Matsuda, T; Maximov, A. N.; Medved, K. S.; Meyer, W; Mielech, A; Mikhailov, Y. U. V.; Moinester, M. A.; Nähle, O; Nassalski, J; Neliba, S; Neyret, D. P.; Nikolaenko, V. I.; Nozdrin, A. A.; Obraztsov, V. F.; Olshevsky, A. G.; Ostrick, M; Padee, A; Pagano, Paolo; Panebianco, S; Panzieri, D; Paul, S; Pereira, H. D.; Peshekhonov, D. V.; Peshekhonov, V. D.; Piragino, G; Platchkov, S; Platzer, K; Pochodzalla, J; Polyakov, V. A.; Popov, A. A.; Pretz, J; Procureur, S; Quintans, C; Ramos, S; Rebourgeard, P. C.; Reicherz, G; Reymann, J; Rith, K; Rondio, E; Rozhdestvensky, A. M.; Sadovski, A. B.; Saller, E; Samoylenko, V. D.; Sandacz, A; Sans, M; Sapozhnikov, M. G.; Savin, I. A.; Schiavon, Paolo; Schill, C; Schmidt, T; Schmitt, H; Schmitt, L; Shevchenko O., Yu; Shishkin, A. A.; Siebert, H. W.; Sinha, L; Sissakian, A. N.; Skachkova, A; Slunecka, M; Smirnov, G. I.; Sozzi, Federica; Srnka, A; Stinzing, F; Stolarski, M; Sugonyaev, V. P.; Sulc, M; Sulej, R; Takabayashi, N; Tchalishev, V. V.; Tessarotto, F; Teufel, A; Thers, D; Tkatchev, L. G.; Toeda, T; Tretyak, V. I.; Trousov, S; Varanda, M; Virius, M; Vlassov, N. V.; Wagner, M; Webb, R; Weise, E; Weitzel, Q; Wiedner, U; Wiesmann, M; Windmolders, R; Wirth, S; Wisblicki, W; Zanetti, A. M.; Zaremba, K; Zhao, J; Ziegler, R; Zvyagin, A.

doi:10.1016/j.physletb.2005.11.049

We present a determination of the gluon polarization DeltaG/G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q2 < 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 6LiD 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 DeltaG/G = 0.024 ± 0.089(stat) ± 0.057(syst) at xg = 0.095 and μ2 ~ 3 (GeV/c)2.

Gluon polarization in the nucleon from quasi-real photoproduction of high-p hadron pairs / AGEEV E., S., ALEXAKHIN V., Y.u., Alexandrov, Y.u., ALEXEEV G., D., Amoroso, A., Badelek, B., BALESTRA E., S., ALEXAKHIN V., Y.u., Alexandrov, Y.u., ALEXEEV G., D., Amoroso, A., Badelek, B., Balestra, F., Ball, J., Baum, G., Bedfer, Y., Berglund, P., Bernet, C., Bertini, R., Birsa, R., et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 633:(2006), pp. 25-32. [10.1016/j.physletb.2005.11.049]