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Suppression of ϒ(1S), ϒ(2S), and ϒ(3S) quarkonium states in PbPb collisions at sNN=2.76TeV

par Khachatryan, Vardan;Brun, Hugues ;Clerbaux, Barbara ;De Lentdecker, Gilles ;Delannoy, Hugo ;Fasanella, Giuseppe ;Favart, Laurent ;Goldouzian, Reza ;Grebenyuk, Anastasia ;Karapostoli, Georgia ;Lenzi, Thomas ;Leonard, Alexandre ;Luetic, Jelena ;Maerschalk, Thierry ;Marinov, Audrey ;Randle-Conde, Aidan Sean ;Seva, Tomislav ;Vander Velde, Catherine ;Vanlaer, Pascal ;Vannerom, David ;Yonamine, Ryo ;Zenoni, Florian ;Zhang, Fengwangdong ;Fang, Wenxing ;Dorney, Brian ;Wang, Qun
Référence Physics letters. Section B, 770, page (357-379)
Publication Publié, 2017

Article révisé par les pairs

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Résumé :

The production yields of ϒ(1S), ϒ(2S), and ϒ(3S) quarkonium states are measured through their decays into muon pairs in the CMS detector, in PbPb and pp collisions at the centre-of-mass energy per nucleon pair of 2.76 TeV. The data correspond to integrated luminosities of 166μb−1 and 5.4pb−1 for PbPb and pp collisions, respectively. Differential production cross sections are reported as functions of ϒ rapidity y up to 2.4, and transverse momentum pT up to 20GeV/c. A strong centrality-dependent suppression is observed in PbPb relative to pp collisions, by factors of up to ≈2 and 8, for the ϒ(1S) and ϒ(2S) states, respectively. No significant dependence of this suppression is observed as a function of y or pT. The ϒ(3S) state is not observed in PbPb collisions, which corresponds to a suppression for the centrality-integrated data by at least a factor of ≈7 at a 95% confidence level. The observed suppression is in agreement with theoretical scenarios modeling the sequential melting of quarkonium states in a quark gluon plasma.