par Chatrchyan, Serguei;Clerbaux, Barbara 
;De Lentdecker, Gilles ;Gay, Arnaud ;Hreus, Tomas ;Marage, Pierre ;Thomas, Laurent ;Vander Velde, Catherine ;Vanlaer, Pascal ;Charaf, Othman ;Dero, Vincent ;Hammad, Grégory ; [et al.]
Référence Physical review letters, 107, 5, 052302
Publication Publié, 2011
;De Lentdecker, Gilles ;Gay, Arnaud ;Hreus, Tomas ;Marage, Pierre ;Thomas, Laurent ;Vander Velde, Catherine ;Vanlaer, Pascal ;Charaf, Othman ;Dero, Vincent ;Hammad, Grégory ; [et al.]Référence Physical review letters, 107, 5, 052302
Publication Publié, 2011
Article révisé par les pairs
| Résumé : | A comparison of the relative yields of Υ resonances in the μ+μ- decay channel in Pb-Pb and pp collisions at a center-of-mass energy per nucleon pair of 2.76TeV is performed with data collected with the CMS detector at the LHC. Using muons of transverse momentum above 4GeV/c and pseudorapidity below 2.4, the double ratio of the Υ(2S) and Υ(3S) excited states to the Υ(1S) ground state in Pb-Pb and pp collisions, [Υ(2S+3S)/Υ(1S)]Pb-Pb/[Υ(2S+3S)/Υ(1S) ]pp, is found to be 0.31-0.15+0.19(stat)±0.03(syst). The probability to obtain the measured value, or lower, if the true double ratio is unity, is calculated to be less than 1%. |
