Affordable Access

Measurement of the prompt J/ψ and ψ(2S) polarizations in pp collisions at √s = 7TeV

Publication Date


The polarizations of prompt J/ψ and ψ(2S) mesons are measured in proton–proton collisions at √s = 7TeV, 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 λ_ϑ, λ_φ, and λ_(ϑφ), as well as the frame-invariant quantity √s = 7TeV, 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<p_T<70 GeV, in the rapidity intervals |y|<0.6 and 0.6<|y|<1.2. The corresponding ψ(2S) results cover 14<p_T<50 GeV and include a third rapidity bin, 1.2<|y|<1.5. No evidence of large polarizations is seen in these kinematic regions, which extend much beyond those previously explored.

There are no comments yet on this publication. Be the first to share your thoughts.