Measurement of quarkonium polarization at CMS

Full text: Studies of the production of quarkonium states are very important to improve our understanding of QCD and hadron formation, given that the heavy quark masses allow the application of theoretical tools less sensitive to nonperturbative effects. This talk presents recent CMS measurements of the polarizations of the Psi and Upsilon states produced in proton-proton collisions at √(s)=7 TeV, in a dimuon sample collected in 2011. The results are measured in bins of dimuon transverse momentum and rapidity, significantly extending the pT and rapidity ranges probed by previous experiments. At high transverse momenta the observations for the Y(3S) and Ψ(2S) are in disagreement with theoretical predictions. (author)