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., 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.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 633:(2006), pp. 25-32. [10.1016/j.physletb.2005.11.049]