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

We present a determination of the gluon polarization Delta 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...

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Detalles Bibliográficos
Autores principales: Ageev, 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, F., Bravar, A., Bressan, A., Brona, G., Burtin, E., Bussa, M.P., Bytchkov, V.N., Cerini, L., Chapiro, A., Cicuttin, A., Colavita, A.A., Colantoni, M., Costa, S., Crespo, M.L., Dalla Torre, S., Dasgupta, S.S., Dedek, N., De Masi, R., Dhara, L., Diaz, V., Dinkelbach, A.M., Dolgopolov, A.V., Donskov, S.V., Dorofeev, V.A., Duic, V., 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., Garfagnini, R., Gautheron, F., Gavrichtchouk, O.P., Geyer, R., Giorgi, M., Gobbo, B., Gorin, A.M., Grajek, O.A., Grasso, A., Grube, B., Hannappel, J., von Harrach, D., Hasegawa, T., Hedicke, S., Hermann, R., Hinterberger, F., von Hodenberg, M., Horikawa, N., 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., Kalinnikov, V., Kang, D., Karstens, F., Kastaun, W., Ketzer, B., Khaustov, G.V., Khokhlov, Yu.A., Khomutov, N.V., Klein, F., Koblitz, S., Kolosov, V.N., Komissarov, E.V., Konoplyannikov, A.K., Konstantinov, V.F., Korentchenko, A.S., Korzenev, A., Koutchinski, N.A., Kowalik, K., Kravchuk, N.P., Krivokhizhin, G.V., Kroumchtein, Z.V., Kuhn, R., Kunne, F., Kurek, K., Ladygin, M.E., 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, A., Marzec, J., Matsuda, T., Maximov, A.N., Medved, K.S., Meyer, W., Mikhailov, Yu.V., Moinester, M.A., Nassalski, J., Neliba, S., Neyret, D.P., Nikolaenko, V.I., Nozdrin, A.A., Obraztsov, V.F., Olshevsky, A.G., Ostrick, M., Padee, A., Pagano, P., Panebianco, S., Paul, S., Peshekhonov, D.V., Peshekhonov, V.D., Piragino, G., Platchkov, S., Platzer, K., Pochodzalla, J., Polyakov, V.A., Popov, A.A., Procureur, S., Quintans, C., Ramos, S., Rebourgeard, P.C., Reicherz, G., Reymann, J., Rondio, E., Rozhdestvensky, A.M., Sadovski, A.B., Saller, E., Samoylenko, V.D., Sandacz, A., Sans, M., Sapozhnikov, M.G., Savin, Igor A., Schiavon, P., Schill, C., Schmidt, T., Schmitt, H., Shevchenko, O.Yu., Shishkin, A.A., Siebert, H.-W., Sinha, L., Sissakian, A.N., Skachkova, A., Slunecka, M., Smirnov, G.I., Sozzi, F., 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., Trusov, Sergey V., Varanda, M., Virius, M., Vlassov, N.V., Wagner, M., Webb, R., Weise, E., Weitzel, Q., Wiedner, U., Wiesmann, M., Windmolders, R., Wirth, S., Wislicki, W., Zanetti, A.M., Zaremba, K., Zhao, J., Ziegler, R., Zvyagin, A.
Lenguaje:eng
Publicado: 2006
Materias:
Particle Physics - Experiment
Acceso en línea:https://dx.doi.org/10.1016/j.physletb.2005.11.049
http://cds.cern.ch/record/906021
Descripción
Sumario:We present a determination of the gluon polarization Delta 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 Delta G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3 (GeV}/c)^2.

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