Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, cilt.727, sa.4-5, ss.381-402, 2013 (SCI-Expanded)
The polarizations of prompt J/ψ and ψ(2S) mesons are measured in proton-proton collisions at s=7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 fb-1. The prompt J/ψ and ψ(2S) polarization parameters λθ{symbol}, λφ, and λθ{symbol}φ, as well as the frame-invariant quantity λ~, are measured from the dimuon decay angular distributions in three different polarization frames. The J/ψ results are obtained in the transverse momentum range 14