Measurements of Quarkonium Production Cross-Sections with the CMS Experiment

Abstract

Using large data samples of dimuon events, CMS has performed detailed measurements of differential cross sections of J/Ψ, Ψ(2S) and ϒ(nS) states, as a function of transverse momentum in several rapidity bins. The measurements reach significantly higher transverse momentum than previously reported. The quarkonium production cross-sections are compared with recent predictions in the context of NLO nonrelativistic QCD.In this talk, we will present a new measurement on ϒ(nS) production cross sections in proton-proton collisions at s=7 TeV. We report the cross section results integrated over the transverse momentum range pT<50 GeV/c and rapidity range |y|<2.4. We also report the measurement of the ϒ(nS) differential cross sections as a function of transverse momentum and rapidity and the cross section ratios ϒ(2S)/ϒ(1S) and ϒ(3S)/ϒ(1S).Finally, we report the very recent measurement of χc2/χc1 production cross-sections, differentially in pT, extending to pT=25 GeV/c, thereby providing an important test of QCD calculations at higher pT than previously possible.