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 λν, λφ, and λνφ, 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.
Original language | English |
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Article number | 081802 |
Number of pages | 15 |
Journal | Physical Review Letters |
Volume | 110 |
Issue number | 8 |
DOIs | |
Publication status | Published - 2013 |
Externally published | Yes |