  The suppression of the individual Upsilon(nS) states in PbPb collisions with
respect to their yields in pp data has been measured. The PbPb and pp data sets
used in the analysis correspond to integrated luminosities of 150 inverse
microbarns and 230 inverse nanobarns, respectively, collected in 2011 by the
CMS experiment at the LHC, at a center-of-mass energy per nucleon pair of 2.76
TeV. The Upsilon(nS) yields are measured from the dimuon invariant mass
spectra. The suppression of the Upsilon(nS) yields in PbPb relative to the
yields in pp scaled by the number of nucleon-nucleon collisions, R[AA], is
measured as a function of the collision centrality. Integrated over centrality,
the R[AA] values are 0.56 +/- 0.08 (stat.) +/- 0.07 (syst.), 0.12 +/- 0.04
(stat.) +/- 0.02 (syst.), and lower than 0.10 (at 95% confidence level), for
the Upsilon(1S), Upsilon(2S), and Upsilon(3S) states, respectively. The results
demonstrate the sequential suppression of the Upsilon(nS) states in PbPb
collisions at LHC energies.
