Publication
Title
Observation of sequential $\Upsilon$ suppression in PbPb collisions
Author
Institution/Organisation
CMS Collaboration
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.
Language
English
Source (journal)
Physical review letters. - New York, N.Y.
Publication
New York, N.Y. : 2012
ISSN
0031-9007
Volume/pages
109:22(2012), p. 1-15
Article Reference
222301
ISI
000311552100002
Medium
E-only publicatie
Full text (Publishers DOI)
Full text (open access)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address