CERN Accelerating science

Article
Report number arXiv:1205.5122 ; CERN-PH-EP-2012-147 ; CERN-PH-EP-2012-147
Title Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Sivers asymmetries
Author(s)

Adolph, C. (Erlangen - Nuremberg U.) ; Alekseev, M.G. (INFN, Trieste) ; Alexakhin, V.Yu. (Dubna, JINR) ; Alexandrov, Yu. (Lebedev Inst.) ; Alexeev, G.D. (Dubna, JINR) ; Amoroso, A. (INFN, Turin ; Turin U.) ; Antonov, A.A. (Dubna, JINR) ; Austregesilo, A. (Munich, Tech. U. ; CERN) ; Badelek, B. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Balestra, F. (INFN, Turin ; Turin U.) ; Barth, J. (Bonn U.) ; Baum, G. (Bielefeld U.) ; Bedfer, Y. (DAPNIA, Saclay) ; Bernhard, J. (Mainz U., Inst. Kernphys.) ; Bertini, R. (INFN, Turin ; Turin U.) ; Bettinelli, M. (Munich U.) ; Bicker, K. (Munich, Tech. U. ; CERN) ; Bieling, J. (Bonn U.) ; Birsa, R. (INFN, Trieste) ; Bisplinghoff, J. (Bonn U.) ; Bordalo, P. (LIP, Lisbon) ; Bradamante, F. (INFN, Trieste ; Trieste U.) ; Braun, C. (Erlangen - Nuremberg U.) ; Bravar, A. (INFN, Trieste) ; Bressan, A. (INFN, Trieste ; Trieste U.) ; Burtin, E. (DAPNIA, Saclay) ; Capozza, L. (DAPNIA, Saclay) ; Chiosso, M. (INFN, Turin ; Turin U.) ; Chung, S.U. (Munich, Tech. U.) ; Cicuttin, A. (INFN, Trieste ; ICTP, Trieste) ; Crespo, M.L. (INFN, Trieste ; ICTP, Trieste) ; Dalla Torre, S. (INFN, Trieste) ; Das, S. (Matrivani Inst., Calcutta) ; Dasgupta, S.S. (Matrivani Inst., Calcutta) ; Dasgupta, S. (Matrivani Inst., Calcutta) ; Denisov, O.Yu. (INFN, Turin) ; Dhara, L. (Matrivani Inst., Calcutta) ; Donskov, S.V. (Serpukhov, IHEP) ; Doshita, N. (Yamagata U.) ; Duic, V. (INFN, Trieste ; Trieste U.) ; Dunnweber, W. (Munich U.) ; Dziewiecki, M. (Warsaw U. of Tech.) ; Efremov, A. (Dubna, JINR) ; Elia, C. (INFN, Trieste ; Trieste U.) ; Eversheim, P.D. (Bonn U.) ; Eyrich, W. (Erlangen - Nuremberg U.) ; Faessler, M. (Munich U.) ; Ferrero, A. (DAPNIA, Saclay) ; Filin, A. (Serpukhov, IHEP) ; Finger, Miroslav (Charles U.) ; Finger, Michael, Jr. (Dubna, JINR) ; Fischer, H. (Freiburg U.) ; Franco, C. (LIP, Lisbon) ; von Hohenesche, N.du Fresne (CERN ; Mainz U., Inst. Kernphys.) ; Friedrich, J.M. (Munich, Tech. U.) ; Frolov, V. (CERN) ; Garfagnini, R. (INFN, Turin ; Turin U.) ; Gautheron, F. (Ruhr U., Bochum) ; Gavrichtchouk, O.P. (Dubna, JINR) ; Gerassimov, S. (Munich, Tech. U. ; Lebedev Inst.) ; Geyer, R. (Munich U.) ; Giorgi, M. (INFN, Trieste ; Trieste U.) ; Gnesi, I. (INFN, Turin ; Turin U.) ; Gobbo, B. (INFN, Trieste) ; Goertz, S. (Bonn U.) ; Grabmuller, S. (Munich, Tech. U.) ; Grasso, A. (INFN, Turin ; Turin U.) ; Grube, B. (Munich, Tech. U.) ; Gushterski, R. (Dubna, JINR) ; Guskov, A. (Dubna, JINR) ; Guthorl, T. (Freiburg U.) ; Haas, F. (Munich, Tech. U.) ; von Harrach, D. (Mainz U., Inst. Kernphys.) ; Heinsius, F.H. (Freiburg U.) ; Herrmann, F. (Freiburg U.) ; Hess, C. (Ruhr U., Bochum) ; Hinterberger, F. (Bonn U.) ; Horikawa, N. (Nagoya U.) ; Hoppner, Ch. (Munich, Tech. U.) ; d'Hose, N. (DAPNIA, Saclay) ; Ishimoto, S. (Yamagata U.) ; Ivanov, O. (Dubna, JINR) ; Ivanshin, Yu. (Dubna, JINR) ; Iwata, T. (Yamagata U.) ; Jahn, R. (Bonn U.) ; Jary, V. (Prague, Tech. U.) ; Jasinski, P. (Mainz U., Inst. Kernphys.) ; Joosten, R. (Bonn U.) ; Kabuss, E. (Mainz U., Inst. Kernphys.) ; Kang, D. (Mainz U., Inst. Kernphys.) ; Ketzer, B. (Munich, Tech. U.) ; Khaustov, G.V. (Serpukhov, IHEP) ; Khokhlov, Yu.A. (Serpukhov, IHEP) ; Kisselev, Yu. (Ruhr U., Bochum) ; Klein, F. (Bonn U.) ; Klimaszewski, K. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Koblitz, S. (Mainz U., Inst. Kernphys.) ; Koivuniemi, J.H. (Ruhr U., Bochum) ; Kolosov, V.N. (Serpukhov, IHEP) ; Kondo, K. (Yamagata U.) ; Konigsmann, K. (Freiburg U.) ; Konorov, I. (Munich, Tech. U. ; Lebedev Inst.) ; Konstantinov, V.F. (Serpukhov, IHEP) ; Korzenev, A. (DAPNIA, Saclay) ; Kotzinian, A.M. (INFN, Turin ; Turin U.) ; Kouznetsov, O. (DAPNIA, Saclay ; Dubna, JINR) ; Kramer, M. (Munich, Tech. U.) ; Kroumchtein, Z.V. (Dubna, JINR) ; Kunne, F. (DAPNIA, Saclay) ; Kurek, K. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Lauser, L. (Freiburg U.) ; Lednev, A.A. (Serpukhov, IHEP) ; Lehmann, A. (Erlangen - Nuremberg U.) ; Levorato, S. (INFN, Trieste ; Trieste U.) ; Lichtenstadt, J. (Tel Aviv U.) ; Liska, T. (Prague, Tech. U.) ; Maggiora, A. (INFN, Turin) ; Magnon, A. (DAPNIA, Saclay) ; Makke, N. (INFN, Trieste ; Trieste U. ; DAPNIA, Saclay) ; Mallot, G.K. (CERN) ; Mann, A. (Munich, Tech. U.) ; Marchand, C. (DAPNIA, Saclay) ; Martin, A. (INFN, Trieste ; Trieste U.) ; Marzec, J. (Warsaw U. of Tech.) ; Matsuda, T. (Miyazaki U.) ; Meshcheryakov, G. (Dubna, JINR) ; Meyer, W. (Ruhr U., Bochum) ; Michigami, T. (Yamagata U.) ; Mikhailov, Yu.V. (Serpukhov, IHEP) ; Moinester, M.A. (Tel Aviv U.) ; Morreale, A. (DAPNIA, Saclay) ; Mutter, A. (Mainz U., Inst. Kernphys. ; Freiburg U.) ; Nagaytsev, A. (Dubna, JINR) ; Nagel, T. (Munich, Tech. U.) ; Negrini, T. (Freiburg U.) ; Nerling, F. (Freiburg U.) ; Neubert, S. (Munich, Tech. U.) ; Neyret, D. (DAPNIA, Saclay) ; Nikolaenko, V.I. (Serpukhov, IHEP) ; Nowak, W.D. (Freiburg U.) ; Nunes, A.S. (LIP, Lisbon) ; Olshevsky, A.G. (Dubna, JINR) ; Ostrick, M. (Mainz U., Inst. Kernphys.) ; Padee, A. (Warsaw U. of Tech.) ; Panknin, R. (Bonn U.) ; Panzieri, D. (INFN, Turin ; Piemonte Orientale U., Alessandria) ; Parsamyan, B. (INFN, Turin ; Turin U.) ; Paul, S. (Munich, Tech. U.) ; Perevalova, E. (Dubna, JINR) ; Pesaro, G. (INFN, Trieste ; Trieste U.) ; Peshekhonov, D.V. (Dubna, JINR) ; Piragino, G. (INFN, Turin ; Turin U.) ; Platchkov, S. (DAPNIA, Saclay) ; Pochodzalla, J. (Mainz U., Inst. Kernphys.) ; Polak, J. (INFN, Trieste ; Trieste U. ; Liberec Tech. U.) ; Polyakov, V.A. (Serpukhov, IHEP) ; Pretz, J. (Bonn U.) ; Quaresma, M. (LIP, Lisbon) ; Quintans, C. (LIP, Lisbon) ; Rajotte, J.F. (Munich U.) ; Ramos, S. (LIP, Lisbon) ; Rapatsky, V. (Dubna, JINR) ; Reicherz, G. (Ruhr U., Bochum) ; Richter, A. (Erlangen - Nuremberg U.) ; Rocco, E. (CERN) ; Rondio, E. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Rossiyskaya, N.S. (Dubna, JINR) ; Ryabchikov, D.I. (Serpukhov, IHEP) ; Samoylenko, V.D. (Serpukhov, IHEP) ; Sandacz, A. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Sapozhnikov, M.G. (Dubna, JINR) ; Sarkar, S. (Matrivani Inst., Calcutta) ; Savin, I.A. (Dubna, JINR) ; Sbrizzai, G. (INFN, Trieste ; Trieste U.) ; Schiavon, P. (INFN, Trieste ; Trieste U.) ; Schill, C. (Freiburg U.) ; Schluter, T. (Munich U.) ; Schmidt, K. (Freiburg U.) ; Schmitt, L. (Munich, Tech. U.) ; Schonning, K. (CERN) ; Schopferer, S. (Freiburg U.) ; Schott, M. (CERN) ; Schroder, W. (Erlangen - Nuremberg U.) ; Shevchenko, O.Yu. (Dubna, JINR) ; Silva, L. (LIP, Lisbon) ; Sinha, L. (Matrivani Inst., Calcutta) ; Sissakian, A.N. (Dubna, JINR) ; Slunecka, M. (Dubna, JINR) ; Smirnov, G.I. (Dubna, JINR) ; Sosio, S. (INFN, Turin ; Turin U.) ; Sozzi, F. (INFN, Trieste) ; Srnka, A. (Inst. Sci. Instruments, Brno) ; Steiger, L. (INFN, Trieste) ; Stolarski, M. (LIP, Lisbon) ; Sulc, M. (Liberec Tech. U.) ; Sulej, R. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Suzuki, H. (Yamagata U.) ; Sznajder, P. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Takekawa, S. (INFN, Turin) ; Wolbeek, J.Ter (Freiburg U.) ; Tessaro, S. (INFN, Trieste) ; Tessarotto, F. (INFN, Trieste) ; Tkatchev, L.G. (Dubna, JINR) ; Uhl, S. (Munich, Tech. U.) ; Uman, I. (Munich U.) ; Vandenbroucke, M. (DAPNIA, Saclay) ; Virius, M. (Prague, Tech. U.) ; Vlassov, N.V. (Dubna, JINR) ; Wang, L. (Ruhr U., Bochum) ; Wilfert, M. (Mainz U., Inst. Kernphys.) ; Windmolders, R. (Bonn U.) ; Wislicki, W. (Warsaw U. ; Democritos Nucl. Res. Ctr.) ; Wollny, H. (DAPNIA, Saclay ; Freiburg U.) ; Zaremba, K. (Warsaw U. of Tech.) ; Zavertyaev, M. (Lebedev Inst.) ; Zemlyanichkina, E. (Dubna, JINR) ; Ziembicki, M. (Warsaw U. of Tech.) ; Zhuravlev, N. (Dubna, JINR) ; Zvyagin, A. (Munich U.)

Publication 2012-10-31
Imprint 17 May 2012
Number of pages 7
Note Comments: 11 pages, 6 figures
11 pages, 6 figures
In: Phys. Lett. B 717 (2012) 383
DOI 10.1016/j.physletb.2012.09.056
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN SPS ; COMPASS NA58
Free keywords QCD ; experimental results ; COMPASS ; SIDIS ; SIVERS asymmetries
Abstract The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV positive muon beam and a transversely polarised NH_3 target. The Sivers asymmetry of the proton has been extracted in the Bjorken x range 0.003<x<0.7. The new measurements have small statistical and systematic uncertainties of a few percent and confirm with considerably better accuracy the previous COMPASS measurement. The Sivers asymmetry is found to be compatible with zero for negative hadrons and positive for positive hadrons, a clear indication of a spin-orbit coupling of quarks in a transversely polarised proton. As compared to measurements at lower energy, a smaller Sivers asymmetry for positive hadrons is found in the region x > 0.03. The asymmetry is different from zero and positive also in the low x region, where sea-quarks dominate. The kinematic dependence of the asymmetry has also been investigated and results are given for various intervals of hadron and virtual photon fractional energy. In contrast to the case of the Collins asymmetry, the results on the Sivers asymmetry suggest a strong dependence on the four-momentum transfer to the nucleon, in agreement with the most recent calculations.
Copyright/License Preprint: © 2012-2024 CERN (License: CC-BY-3.0)

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