The polarised valence quark distribution from semi-inclusive DIS

Journal Article (Journal Article)

The semi-inclusive difference asymmetry Ah+ - 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 6LiD target in the kinematic range 0.006 < x < 0.7 and 1 < Q2 < 100   (GeV / c)2. In leading order QCD (LO) the deuteron asymmetry Ah+ - h- measures the valence quark polarisation and provides an evaluation of the first moment of Δ uv + Δ dv which is found to be equal to 0.40 ± 0.07 (stat.) ± 0.06 (syst.) over the measured range of x at Q2 = 10   (GeV / c)2. When combined with the first moment of g1d previously measured on the same data, this result favours a non-symmetric polarisation of light quarks Δ over(u, ̄) = - Δ over(d, ̄) at a confidence level of two standard deviations, in contrast to the often assumed symmetric scenario Δ over(u, ̄) = Δ over(d, ̄) = Δ over(s, ̄) = Δ s. © 2008 Elsevier B.V. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Alekseev, M; Alexakhin, VY; Alexandrov, Y; Alexeev, GD; Amoroso, A; Arbuzov, A; Badełek, 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, MP; Chapiro, A; Chiosso, M; Cicuttin, A; Colantoni, M; Costa, S; Crespo, ML; Dalla Torre, S; Dafni, T; Das, S; Dasgupta, SS; De Masi, R; Dedek, N; Denisov, OY; Dhara, L; Diaz, V; Dinkelbach, AM; Donskov, SV; Dorofeev, VA; Doshita, N; Duic, V; Dünnweber, W; Eversheim, PD; Eyrich, W; Faessler, M; Falaleev, V; Ferrero, A; Ferrero, L; Finger, M; Fischer, H; Franco, C; Franz, J; Friedrich, JM; Frolov, V; Garfagnini, R; Gautheron, F; Gavrichtchouk, OP; Gazda, R; Gerassimov, S; Geyer, R; Giorgi, M; Gobbo, B; Goertz, S; Gorin, AM; Grabmüller, S; Grajek, OA; Grasso, A; Grube, B; Gushterski, R; Guskov, A; Haas, F; Hannappel, J; von Harrach, D; Hasegawa, T; Heckmann, J; Hedicke, S; Heinsius, FH; Hermann, R; Heß, C; Hinterberger, F; von Hodenberg, M; Horikawa, N; Horikawa, S; d'Hose, N; Ilgner, C; Ioukaev, AI; Ishimoto, S; Ivanov, O; Ivanshin, Y; Iwata, T; Jahn, R; Janata, A; Jasinski, P; Joosten, R; Jouravlev, NI; Kabuß, E

Published Date

  • March 6, 2008

Published In

Volume / Issue

  • 660 / 5

Start / End Page

  • 458 - 465

International Standard Serial Number (ISSN)

  • 0370-2693

Digital Object Identifier (DOI)

  • 10.1016/j.physletb.2007.12.056

Citation Source

  • Scopus