The ALICE Collaboration has studied J/psi production in pp collisions at sqrt(s)=7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/psi polarization parameters lambda_theta and lambda_phi were obtained. The study was performed in the kinematic region 2.5<y<4, 2<p_t<8 GeV/c, in the helicity and Collins-Soper reference frames. The results for lambda_theta in the helicity frame show a longitudinal polarization at low p_t, vanishing with increasing transverse momentum. All the other polarization parameters are consistent with zero, within uncertainties.

J/ψ Polarization in pp Collisions at sqrt[s]=7  TeV

BEOLE', Stefania;L. Bianchi;CORRALES MORALES, YASSER;FERRETTI, Alessandro;GAGLIARDI, Martino;GALLIO, Mauro;INNOCENTI, GIAN MICHELE;MARCHISONE, MASSIMILIANO;MASERA, Massimo;MILANO, LEONARDO;ORTONA, GIACOMO;VERCELLIN, Ermanno;
2012-01-01

Abstract

The ALICE Collaboration has studied J/psi production in pp collisions at sqrt(s)=7 TeV at the LHC through its muon pair decay. The polar and azimuthal angle distributions of the decay muons were measured, and results on the J/psi polarization parameters lambda_theta and lambda_phi were obtained. The study was performed in the kinematic region 2.5
2012
108
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B. Abelev;A. Abrahantes Quintana;D. Adamová;A. Adare;M. Aggarwal;G. Aglieri Rinella;A. Agocs;A. Agostinelli;S. Aguilar Salazar;Z. Ahammed;N....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/109328
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