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

Journal Article (Journal Article)

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, Δū-sΔd̄, is found to be slightly positive, about 1.5 standard deviations away from zero. © 2010 Elsevier B.V.

Full Text

Duke Authors

Cited Authors

  • Alekseev, MG; Alexakhin, V; Alexandrov, Y; Alexeev, GD; Amoroso, A; Austregesilo, A; 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, MP; Chaberny, D; Chiosso, M; Chung, SU; Cicuttin, A; Colantoni, M; Crespo, ML; Torre, SD; Das, S; Dasgupta, SS; Denisov, OY; Dhara, L; Diaz, V; Donskov, SV; Doshita, N; Duic, V; Dünnweber, W; Efremov, A; El Alaoui, A; Eversheim, PD; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Fischer, H; Franco, C; Friedrich, JM; Garfagnini, R; Gautheron, F; Gavrichtchouk, OP; 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, FH; Herrmann, F; Heß, C; Hinterberger, F; Horikawa, N; Höppner, C; d'Hose, N; Ilgner, C; Ishimoto, S; Ivanov, O; Ivanshin, Y; Iwata, T; Jahn, R; Jasinski, P; Jegou, G; Joosten, R; Kabuß, E; Kang, D; Ketzer, B; Khaustov, GV; Khokhlov, YA; Kisselev, Y; Klein, F; Klimaszewski, K; Koblitz, S; Koivuniemi, JH; Kolosov, VN; Kondo, K; Königsmann, K; Konopka, R; Konorov, I; Konstantinov, VF

Published Date

  • January 1, 2010

Published In

Volume / Issue

  • 693 / 3

Start / End Page

  • 227 - 235

International Standard Serial Number (ISSN)

  • 0370-2693

Digital Object Identifier (DOI)

  • 10.1016/j.physletb.2010.08.034

Citation Source

  • Scopus