/ hep-ex CMS-HIN-16-008

Suppression of excited Upsilon states relative to the ground state in PbPb collisions at sqrt(sNN) = 5.02 TeV

Abstract: The relative yields of Upsilon mesons produced in pp and PbPb collisions at sqrt(s[NN]) = 5.02 TeV and reconstructed via the dimuon decay channel are measured using data collected by the CMS experiment. Double ratios are formed by comparing the yields of the excited states, Upsilon(2S) and Upsilon(3S), to the ground state, Upsilon(1S), in both PbPb and pp collisions at the same center-of-mass energy. The double ratios, [Upsilon(nS)/Upsilon(1S)](PbPb)/[Upsilon(nS)/Upsilon(1S)](pp), are measured to be 0.308 +/- 0.055 (stat) +/- 0.019 (syst) for the Upsilon(2S) and less than 0.26 at 95% confidence level for the Upsilon(3S). No significant Upsilon(3S) signal is found in the PbPb data. The double ratios are studied as a function of collision centrality, as well as dimuon transverse momentum and rapidity. No significant dependencies are observed.

Note: *Temporary entry*; Submitted to Phys. Rev. Lett. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-16-008

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