The Polarised Valence Quark Distribution from semi-inclusive DIS

The semi-inclusive difference asymmetry A^{h+ - h-} for hadrons of opposite charge has been measured by the COMPASS experiment at CERN. The data were collected in the years 2002-2004 using a 160 GeV polarised muon beam scattered off a large polarised 6-LiD target and cover the range 0.006 < x <...

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Detalles Bibliográficos
Autores principales: Alekseev, M., Alexakhin, V.Yu., Alexandrov, Yu., Alexeev, G.D., Amoroso, A., Arbuzov, A., Badelek, B., Balestra, F., Ball, J., Barth, J., Baum, G., Bedfer, Y., Bernet, C., Bertini, R., Bettinelli, M., Birsa, R., Bisplinghoff, J., Bordalo, P., Bradamante, F., Bravar, A., Bressan, A., Brona, G., Burtin, E., Bussa, M.P., Chapiro, A., Chiosso, M., Cicuttin, A., Colantoni, M., Costa, S., Crespo, M.L., Dalla Torre, S., Dafni, T., Das, S., Dasgupta, S.S., De Masi, R., Dedek, N., Denisov, O.Yu., Dhara, L., Diaz, V., Dinkelbach, A.M., Donskov, S.V., Dorofeev, V.A., Doshita, N., Duic, V., Dunnweber, W., Eversheim, P.D., Eyrich, W., Faessler, M., Falaleev, V., Ferrero, A., Ferrero, L., Finger, M., Finger, M., Jr., Fischer, H., Franco, C., Franz, J., Friedrich, J.M., Frolov, V., Garfagnini, R., Gautheron, F., Gavrichtchouk, O.P., Gazda, R., Gerassimov, S., Geyer, R., Giorgi, M., Gobbo, B., Goertz, S., Gorin, A.M., Grabmuller, S., Grajek, O.A., Grasso, A., Grube, B., Gushterski, R., Guskov, A., Haas, F., Hannappel, J., von Harrach, D., Hasegawa, T., Heckmann, J., Hedicke, S., Heinsius, F.H., Hermann, R., Hess, C., Hinterberger, F., von Hodenberg, M., Horikawa, N., Horikawa, S., d'Hose, N., Ilgner, C., Ioukaev, A.I., Ishimoto, S., Ivanov, O., Ivanshin, Yu., Iwata, T., Jahn, R., Janata, A., Jasinski, P., Joosten, R., Jouravlev, N.I., Kabuss, E., Kang, D., Ketzer, B., Khaustov, G.V., Khokhlov, Yu.A., Kisselev, Yu., Klein, F., Klimaszewski, K., Koblitz, S., Koivuniemi, J.H., Kolosov, V.N., Komissarov, E.V., Kondo, K., Konigsmann, K., Konorov, I., Konstantinov, V.F., Korentchenko, A.S., Korzenev, A., Kotzinian, A.M., Koutchinski, N.A., Kouznetsov, O., Kral, A., Kravchuk, N.P., Kroumchtein, Z.V., Kuhn, R., Kunne, F., Kurek, K., Ladygin, M.E., Lamanna, M., Le Goff, J.M., Lednev, A.A., Lehmann, A., Levorato, S., Lichtenstadt, J., Liska, T., Ludwig, I., Maggiora, A., Maggiora, M., Magnon, A., Mallot, G.K., Mann, A., Marchand, C., Marroncle, J., Martin, A., Marzec, J., Massmann, F., Matsuda, T., Maximov, A.N., Meyer, W., Mielech, A., Mikhailov, Yu.V., Moinester, M.A., Mutter, A., Nagaytsev, A., Nagel, T., Nahle, O., Nassalski, J., Neliba, S., Nerling, F., Neubert, S., Neyret, D.P., Nikolaenko, V.I., Nikolaev, K., Olshevsky, A.G., Ostrick, M., Padee, A., Pagano, P., Panebianco, S., Panknin, R., Panzieri, D., Paul, S., Pawlukiewicz-Kaminska, B., Peshekhonov, D.V., Peshekhonov, V.D., Piragino, G., Platchkov, S., Pochodzalla, J., Polak, J., Polyakov, V.A., Pretz, J., Procureur, S., Quintans, C., Rajotte, J.F., Ramos, S., Rapatsky, V., Reicherz, G., Reggiani, D., Richter, A., Robinet, F., Rocco, E., Rondio, E., Rozhdestvensky, A.M., Ryabchikov, D.I., Samoylenko, V.D., Sandacz, A., Santos, H., Sapozhnikov, M.G., Sarkar, S., Savin, I.A., Schiavon, P., Schill, C., Schmitt, L., Schonmeier, P., Schroder, W., Shevchenko, O.Yu., Siebert, H.W., Silva, L., Sinha, L., Sissakian, A.N., Slunecka, M., Smirnov, G.I., Sosio, S., Sozzi, F., Srnka, A., Stinzing, F., Stolarski, M., Sugonyaev, V.P., Sulc, M., Sulej, R., Tchalishev, V.V., Tessaro, S., Tessarotto, F., Teufel, A., Tkatchev, L.G., Venugopal, G., Virius, M., Vlassov, N.V., Vossen, A., Webb, R., Weise, E., Weitzel, Q., Windmolders, R., Wirth, S., Wislicki, W., Wollny, H., Zaremba, K., Zavertyaev, M., Zemlyanichkina, E., Zhao, J., Ziegler, R., Zvyagin, A.
Lenguaje:eng
Publicado: 2007
Materias:
Particle Physics - Experiment
Acceso en línea:https://dx.doi.org/10.1016/j.physletb.2007.12.056
http://cds.cern.ch/record/1048824
Descripción
Sumario:The semi-inclusive difference asymmetry A^{h+ - h-} for hadrons of opposite charge has been measured by the COMPASS experiment at CERN. The data were collected in the years 2002-2004 using a 160 GeV polarised muon beam scattered off a large polarised 6-LiD target and cover the range 0.006 < x < 0.7 and 1 < Q^2 < 100 (GeV/c)^2. In leading order QCD (LO) the asymmetry A_d^{h+ - h-} measures the valence quark polarisation and provides an evaluation of the first moment of Delta u_v + Delta d_v which is found to be equal to 0.40 +- 0.07 (stat.) +- 0.05 (syst.) over the measured range of x at Q^2 = 10 (GeV/c)^2. When combined with the first moment of g_1^d previously measured on the same data, this result favours a non-symmetric polarisation of light quarks Delta u-bar = -Delta d-bar at a confidence level of two standard deviations, in contrast to the often assumed symmetric scenario Delta u-bar = Delta d-bar = Delta s-bar = Delta s.

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