Measurement of bottomonium production in PbPb collisions at sNN=2.76TeV with CMS

The three ϒ states (1S, 2S, 3S) were separated using the Compact Muon Solenoid (CMS) experimental apparatus via their dimuon decays in both pp and heavy-ion collisions. A suppression of the ϒ(1S), ϒ(2S) and ϒ(3S) mesons is observed in PbPb collisions at sNN=2.76TeV, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. Furthermore, a suppression of the excited ϒ(2S) state has been measured with respect to the ϒ(1S) state, expressed as a double ratio [ϒ(2S)/ϒ(1S)]PbPb/[ϒ(2S)/ϒ(1S)]pp. The centrality dependence of the double ratio, as well as the nuclear modification factors (RAA) of the ϒ(1S) and ϒ(2S) states are presented as a function of collision centrality, based on the analysis of the full data sample collected during the 2011 PbPb run, which corresponds to an integrated luminosity of 150μb−1. Upper limits for ϒ(3S), for both the RAA and the double ratio, were also calculated.