Measurement of the υ(1S), υ(2S), and υ(3S) polarizations in pp collisions at √s=7 TeV


Chatrchyan S., Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Aguilo E., ...More

Physical Review Letters, vol.110, no.8, 2013 (SCI-Expanded, Scopus) identifier identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 110 Issue: 8
  • Publication Date: 2013
  • Doi Number: 10.1103/physrevlett.110.081802
  • Journal Name: Physical Review Letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Yıldız Technical University Affiliated: Yes

Abstract

The polarizations of the υ(1S), υ(2S), and υ(3S) mesons are measured in proton-proton collisions at √s=7 TeV, using a data sample of υ(nS)→μ+μ- decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb-1. The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization parameters λ™, λφ, and λ, as well as the frame-invariant quantity λ, are presented as a function of the υ(nS) transverse momentum between 10 and 50 GeV, in the rapidity ranges |y|<0.6 and 0.6<|y|<1.2. No evidence of large transverse or longitudinal polarizations is seen in the explored kinematic region. © 2013 CERN.