The polarised valence quark distribution from semi-inclusive DIS

M. Alekseev, V. Yu Alexakhin, Yu Alexandrov, G. D. Alexeev, A. Amoroso, A. Arbuzov, B. Badełek, F. Balestra, J. Ball, J. Barth, G. Baum, Y. Bedfer, C. Bernet, R. Bertini, M. Bettinelli, R. Birsa, J. Bisplinghoff, P. Bordalo, F. Bradamante, A. BravarA. Bressan, G. Brona, E. Burtin, M. P. Bussa, A. Chapiro, M. Chiosso, A. Cicuttin, M. Colantoni, S. Costa, M. L. Crespo, S. Dalla Torre, T. Dafni, S. Das, S. S. Dasgupta, R. De Masi, N. Dedek, O. Yu Denisov, L. Dhara, V. Diaz, A. M. Dinkelbach, S. V. Donskov, V. A. Dorofeev, N. Doshita, V. Duic, W. Dünnweber, P. D. Eversheim, W. Eyrich, M. Faessler, V. Falaleev, A. Ferrero, L. Ferrero, M. Finger, M. Finger, H. Fischer, C. Franco, J. Franz, J. M. Friedrich, V. Frolov, R. Garfagnini, F. Gautheron, O. P. Gavrichtchouk, R. Gazda, S. Gerassimov, R. Geyer, M. Giorgi, B. Gobbo, S. Goertz, A. M. Gorin, S. Grabmüller, O. A. Grajek, A. Grasso, B. Grube, R. Gushterski, A. Guskov, F. Haas, J. Hannappel, D. von Harrach, T. Hasegawa, J. Heckmann, S. Hedicke, F. H. Heinsius, R. Hermann, C. Heß, F. Hinterberger, M. von Hodenberg, N. Horikawa, S. Horikawa, N. d'Hose, C. Ilgner, A. I. Ioukaev, S. Ishimoto, O. Ivanov, Yu Ivanshin, T. Iwata, R. Jahn, A. Janata, P. Jasinski, R. Joosten, N. I. Jouravlev, E. Kabuß, D. Kang, B. Ketzer, G. V. Khaustov, Yu A. Khokhlov, Yu Kisselev, F. Klein, K. Klimaszewski, S. Koblitz, J. H. Koivuniemi, V. N. Kolosov, E. V. Komissarov, K. Kondo, K. Königsmann, I. Konorov, V. F. Konstantinov, A. S. Korentchenko, A. Korzenev, A. M. Kotzinian, N. A. Koutchinski, O. Kouznetsov, A. Kral, N. P. Kravchuk, Z. V. Kroumchtein, R. Kuhn, F. Kunne, K. Kurek, M. E. Ladygin, M. Lamanna, J. M. Le Goff, A. A. Lednev, A. Lehmann, S. Levorato, J. Lichtenstadt, T. Liska, I. Ludwig, A. Maggiora, M. Maggiora, A. Magnon, G. K. Mallot, A. Mann, C. Marchand, J. Marroncle, A. Martin, J. Marzec, F. Massmann, T. Matsuda, A. N. Maximov, W. Meyer, A. Mielech, Yu V. Mikhailov, M. A. Moinester, A. Mutter, A. Nagaytsev, T. Nagel, O. Nähle, J. Nassalski, S. Neliba, F. Nerling, S. Neubert, D. P. Neyret, V. I. Nikolaenko, K. Nikolaev, A. G. Olshevsky, M. Ostrick, A. Padee, P. Pagano, S. Panebianco, R. Panknin, D. Panzieri, S. Paul, B. Pawlukiewicz-Kaminska, D. V. Peshekhonov, V. D. Peshekhonov, G. Piragino, S. Platchkov, J. Pochodzalla, J. Polak, V. A. Polyakov, J. Pretz, S. Procureur, C. Quintans, J. F. Rajotte, S. Ramos, V. Rapatsky, G. Reicherz, D. Reggiani, A. Richter, F. Robinet, E. Rocco, E. Rondio, A. M. Rozhdestvensky, D. I. Ryabchikov, V. D. Samoylenko, A. Sandacz, H. Santos, M. G. Sapozhnikov, S. Sarkar, I. A. Savin, P. Schiavon, C. Schill, L. Schmitt, P. Schönmeier, W. Schröder, O. Yu Shevchenko, H. W. Siebert, L. Silva, L. Sinha, A. N. Sissakian, M. Slunecka, G. I. Smirnov, S. Sosio, F. Sozzi, A. Srnka, F. Stinzing, M. Stolarski, V. P. Sugonyaev, M. Sulc, R. Sulej, V. V. Tchalishev, S. Tessaro, F. Tessarotto, A. Teufel, L. G. Tkatchev, G. Venugopal, M. Virius, N. V. Vlassov, A. Vossen, R. Webb, E. Weise, Q. Weitzel, R. Windmolders, S. Wirth, W. Wiślicki, H. Wollny, K. Zaremba, M. Zavertyaev, E. Zemlyanichkina, J. Zhao, R. Ziegler, A. Zvyagin

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish
Pages (from-to)458-465
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume660
Issue number5
DOIs
StatePublished - 6 Mar 2008

Keywords

  • Deep inelastic scattering
  • Structure functions

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