Quark helicity distributions from longitudinal spin asymmetries in muon-proton and muon-deuteron scattering

0351515 - ÚPT 2011 RIV NL eng J - Journal Article
Alekseev, M. - Alexakhin, V. Yu. - Alexandrov, Yu. - Alexeev, G. D. - Amoroso, A. - Austregisilio, A. - Badelek, B. - Balestra, F. - Barth, J. - Baum, G. - Bedfer, Y. - Bernhard, J. - Bertini, R. - Bettinelli, M. - Birsa, R. - Bisplinghoff, J. - Bordalo, P. - Bradamante, F. - Bravar, A. - Bressan, A. - Brona, G. - Burtin, E. - Bussa, M. - Chaberny, D. - Chiosso, M. - Chung, S.U. - Cicuttin, A. - Colantoni, M. - Crespo, M. - Dalla Torre, S. - Das, S. - Dasgupta, S. S. - Denisov, O. - Dhara, L. - Diaz, V. - Donskov, S. - Doshita, N. - Duic, V. - Dünnweber, W. - Efremov, A.V. - El Alaoui, A. - Eversheim, P. - Eyrich, W. - Faessler, M. - Ferrero, A. - Filin, A. - Finger, M. - Finger jr., M. - Fischer, H. - Franco, C. - Friedrich, J. - Garfagnini, R. - Gautheron, F. - Gavrichtchouk, O. - Gazda, R. - Gerassimov, S. - Geyer, R. - Giorgi, M. - Gnesi, I. - Gobbo, B. - Goertz, S. - Grabmüller, S. - Grasso, A. - Grube, B. - Gushterski, R. - Guskov, A. - Haas, F. - von Harrach, D. - Hasegawa, T. - Heinsius, F. - Herrmann, F. - Hess, C. - Hinterberger, F. - Horikawa, N. - Höppner, Ch. - d'Hose, N. - Ilgner, C. - Ishimoto, S. - Ivanov, O. - Ivanshin, Yu. - Iwata, T. - Jahn, R. - Jasinski, P. - Jegou, G. - Joosten, R. - Kabuss, E. - Kang, D. - Ketzer, B. - Khaustov, G. - Khokhlov, Y. - Kisselev, Y. - Klein, F. - Klimaszewski, K. - Koblitz, S. - Koivuniemi, J. - Kolosov, V. - Kondo, K. - Königsmann, K. - Konopka, R. - Konorov, I. - Konstantinov, V. - Korzenev, A. - Kotzinian, A. - Kouznetsov, O. - Kowalik, K. - Krämer, M. - Kral, A. - Kroumchtein, Z. - Kuhn, R. - Kunne, F. - Kurek, K. - Lauser, L. - Le Goff, J. - Lednev, A. - Lehmann, A. - Levorato, S. - Lichtenstadt, J. - Liska, T. - Maggiora, A. - Maggiora, M. - Magnon, A. - Makke, N. - Mallot, G. - Mann, A. - Marchand, C. - Martin, A. - Marzec, J. - Massmann, F. - Matsuda, T. - Meyer, W. - Michigami, T. - Mikhailov, Y. - Moinester, M. - Mutter, A. - Nagaytsev, A. - Nagel, T. - Nassalski, J. - Negrini, S. - Nerling, F. - Neubert, S. - Neyret, D. - Nikolaenko, V. - Nunes, A.S. - Olshevsky, A. - Ostrick, M. - Padee, A. - Panknin, R. - Panzieri, D. - Parsamyan, B. - Paul, S. - Pawlukiewicz-Kaminska, B. - Perevalova, E. - Pesaro, G. - Peshekhonov, D. - Piragino, G. - Platchkov, S. - Pochodzalla, J. - Polak, J. - Polyakov, V. - Pontecorvo, G. - Pretz, J. - Quintans, C. - Rajotte, J. - Ramos, S. - Rapatsky, V. - Reicherz, G. - Richter, A. - Robinet, F. - Rocco, E. - Rondio, E. - Ryabchikov, D. - Samoylenko, V. - Sandacz, A. - Santos, H. - Sapozhnikov, M. - Sarkar, S. - Savin, I. - Sbrizzai, G. - Schiavon, P. - Schill, C. - Schlütter, T. - Schmitt, L. - Schopferer, S. - Schröder, W. - Shevchenko, O. - Siebert, H. - Silva, L. - Sinha, L. - Sissakian, A. - Slunecka, M. - Smirnov, G. - Sosio, S. - Sozzi, F. - Srnka, Aleš - Stolarski, M. - Sulc, M. - Sulej, R. - Takekawa, S. - Tessaro, S. - Tessarotto, F. - Teufel, A. - Tkatchev, L. - Uhl, S. - Uman, I. - Virius, M. - Vlassov, N. - Vossen, A. - Weitzel, Q. - Windmolders, R. - Wislicki, W. - Wollny, H. - Zaremba, K. - Zavertyaev, M. - Zemlyanichkina, E. - Ziembicki, M. - Zhao, J. - Zhuravlev, N. - Zvyagin, A.
Quark helicity distributions from longitudinal spin asymmetries in muon-proton and muon-deuteron scattering.
Physics Letters. B. Roč. 693, č. 3 (2010), s. 227-235. ISSN 0370-2693. E-ISSN 1873-2445
R&D Projects: GA MŠMT ME 492
Institutional research plan: CEZ:AV0Z20650511
Keywords : semi-inclusive deep inelastic scattering * structure function * parton distribution functions
Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders
Impact factor: 5.255, year: 2010

Double-spin asymmetries for production of charged pions and kaons in semi-inclusive deep-inelastic muon scattering have been measured by the COMPASS experiment at CERN. The data, obtained by scattering a 160 GeV muon beam off a longitudinally polarised NH3 target, cover a range of the Bjorken variable x between 0.004 and 0.7. A leading order evaluation of the helicity distributions for the three lightest quarks and antiquark flavours derived from these asymmetries and from our previous deuteron data is presented. The resulting values of the sea quark distributions are small and do not show any sizable dependence on x in the range of the measurements. No significant difference is observed between the strange and antistrange helicity distributions, both compatible with zero. The integrated value of the flavour asymmetry of the helicity distribution of the light-quark sea, is found to be slightly positive, about 1.5 standard deviations away from zero.
Permanent Link: http://hdl.handle.net/11104/0191251