Measurement of bottomonium states in pp, pPb and PbPb collisions at 2.76 TeV from CMS

The bottomonium is one of the cleanest probes to study the characteristics of the quark-gluon plasma (QGP) as they are produced at the early stage of collision through hard scattering. The relative production cross section, the nuclear modification factor {\ensuremath{R_{\rm AA}}} has been studied and strong suppression was found in PbPb collisions. The {\ensuremath{R_{\rm AA}}} has been obtained in centrality intervals for {\upsione}{\ensuremath{\Upsilon\textrm{(1S)}}} and {\upsione}{\ensuremath{\Upsilon\textrm{(2S)}}} and also reported a as a function of pT and rapidity. Also the yield ratios of the excited states {\upsione}{\ensuremath{\Upsilon\textrm{(nS)}}} compared to the ground state {\upsione}{\ensuremath{\Upsilon\textrm{(1S)}}} in both pp and PbPb collisions are combined to form the double ratio, which is equivalent to the ratio of the nuclear modification factor {\ensuremath{R_{\rm AA}}}. This quantity has been studied for the two excited states {\upsione}{\ensuremath{\Upsilon\textrm{(2S)}}} and {\upsione}{\ensuremath{\Upsilon\textrm{(3S)}}} in pPb and PbPb collisions.