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.

Chatrchyan, S., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Aguilo, E., et al. (2012). Observation of Sequential upsilon Suppression in PbPb Collisions. PHYSICAL REVIEW LETTERS, 109(22) [10.1103/PhysRevLett.109.222301].

Observation of Sequential upsilon Suppression in PbPb Collisions

BENAGLIA, ANDREA DAVIDE;DE GUIO, FEDERICO;DI MATTEO, LEONARDO;FIORENDI, SARA;GHEZZI, ALESSIO;MANZONI, RICCARDO ANDREA;MARTELLI, ARABELLA;MASSIRONI, ANDREA;MORONI, LUIGI;PAGANONI, MARCO;RAGAZZI, STEFANO;TABARELLI DE FATIS, TOMMASO;Branca, A;GOVONI, PIETRO;DINARDO, MAURO EMANUELE;
2012

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.
Articolo in rivista - Articolo scientifico
high energy collider; LHC; CMS; Pb-Pb collisions
English
2012
109
22
none
Chatrchyan, S., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Aguilo, E., et al. (2012). Observation of Sequential upsilon Suppression in PbPb Collisions. PHYSICAL REVIEW LETTERS, 109(22) [10.1103/PhysRevLett.109.222301].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/46489
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