Observation of Sequential upsilon Suppression in PbPb Collisions

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Abstract

The suppression of the individual gamma (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 mu b(-1) and 230 nb(-1), 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 gamma (nS) yields are measured from the dimuon invariant mass spectra. The suppression of the gamma (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 gamma (1S), gamma (2S), and gamma (3S) states, respectively. The results demonstrate the sequential suppression of the gamma (nS) states in PbPb collisions at LHC energies.

Autore Pugliese

Tutti gli autori

  • Creanza D , De Filippis N , Iaselli G , Maggi G , MY S , Pugliese G , et al.

Titolo volume/Rivista

PHYSICAL REVIEW LETTERS

Anno di pubblicazione

2012

ISSN

0031-9007

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

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Numero di citazioni Scopus

58

Ultimo Aggiornamento Citazioni

2017-04-23 03:20:56

Settori ERC

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Codici ASJC

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