https://doi.org/10.1140/epjc/s10052-010-1461-9
Azimuthal asymmetries of charged hadrons produced by high-energy muons scattered off longitudinally polarised deuterons
1
Fakultät für Physik, Universität Bielefeld, 33501, Bielefeld, Germany
2
Institut für Experimentalphysik, Universität Bochum, 44780, Bochum, Germany
3
Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, 53115, Bonn, Germany
4
Physikalisches Institut, Universität Bonn, 53115, Bonn, Germany
5
Institute of Scientific Instruments, AS CR, 61264, Brno, Czech Republic
6
Matrivani Institute of Experimental Research & Education, Calcutta, 700 030, India
7
Joint Institute for Nuclear Research, 141980, Dubna, Moscow region, Russia
8
Physikalisches Institut, Universität Erlangen–Nürnberg, 91054, Erlangen, Germany
9
Physikalisches Institut, Universität Freiburg, 79104, Freiburg, Germany
10
CERN, 1211, Geneva 23, Switzerland
11
Technical University in Liberec, 46117, Liberec, Czech Republic
12
LIP, 1000-149, Lisbon, Portugal
13
Institut für Kernphysik, Universität Mainz, 55099, Mainz, Germany
14
University of Miyazaki, Miyazaki, 889-2192, Japan
15
Lebedev Physical Institute, 119991, Moscow, Russia
16
Department für Physik, Ludwig-Maximilians-Universität München, 80799, Munich, Germany
17
Physik Department, Technische Universität München, 85748, Garching, Germany
18
Nagoya University, 464, Nagoya, Japan
19
Faculty of Mathematics and Physics, Charles University in Prague, 18000, Prague, Czech Republic
20
Czech Technical University in Prague, 16636, Prague, Czech Republic
21
Institute for High Energy Physics, State Research Center of the Russian Federation, 142281, Protvino, Russia
22
CEA IRFU/SPhN Saclay, 91191, Gif-sur-Yvette, France
23
School of Physics and Astronomy, Tel Aviv University, 69978, Tel Aviv, Israel
24
Trieste Section of INFN, 34127, Trieste, Italy
25
Department of Physics and Trieste Section of INFN, University of Trieste, 34127, Trieste, Italy
26
Abdus Salam ICTP and Trieste Section of INFN, 34127, Trieste, Italy
27
Department of Physics and Torino Section of INFN, University of Turin, 10125, Turin, Italy
28
Torino Section of INFN, 10125, Turin, Italy
29
1500 Alessandria, and Torino Section of INFN, University of Eastern Piedmont, 10125, Turin, Italy
30
Sołtan Institute for Nuclear Studies and University of Warsaw, 00-681, Warsaw, Poland
31
Institute of Radioelectronics, Warsaw University of Technology, 00-665, Warsaw, Poland
32
Yamagata University, Yamagata, 992-8510, Japan
Received:
9
July
2010
Revised:
14
September
2010
Published online:
15
October
2010
Azimuthal asymmetries in semi-inclusive production of positive (h
+) and negative hadrons (h
−) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The asymmetries were decomposed in several terms according to their expected modulation in the azimuthal angle φ of the outgoing hadron. Each term receives contributions from one or several spin and transverse-momentum-dependent parton distribution and fragmentation functions. The amplitudes of all φ-modulation terms of the hadron asymmetries integrated over the kinematic variables are found to be consistent with zero within statistical errors, while the constant terms are nonzero and equal for h
+ and h
− within the statistical errors. The dependencies of the φ-modulated terms versus the Bjorken momentum fraction x, the hadron fractional momentum z, and the hadron transverse momentum were studied. The x dependence of the constant terms for both positive and negative hadrons is in agreement with the longitudinal double-spin hadron asymmetries, measured in semi-inclusive deep-inelastic scattering. The x dependence of the sin φ-modulation term is less pronounced than that in the corresponding HERMES data. All other dependencies of the φ-modulation amplitudes are consistent with zero within the statistical errors.
© Springer-Verlag / Società Italiana di Fisica, 2010