Abstract
The sequential suppression of the individual Υ states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp datasets used in these proceedings correspond to integrated luminosities of 150/μb and 230/nb, respectively, collected by the CMS experiment at the LHC at 2.76 TeV in 2011. The relative suppression of the excited Υ states has been measured with respect to the Υ(1S) ground state, expressed as a double ratio [Υ(nS)/Υ(1S)]pbPb/[Υ(nS)/Υ(1S)]pp. The absolute suppression of the Υ(nS) yields in PbPb relative to the yields in pp scaled by the number of nucleon-nucleon collisions, RAA, is measured as a function of the collision centrality. Integrated over centrality, the RAA values for Υ(1S), Υ(2S), and the upper limit of Υ(3S) RAA are reported in this proceeding, which demonstrate the sequential suppression of the Υ(nS) states in PbPb collisions at LHC energies.
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