The nuclear modification factors of J/ψ and ψ(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of √s_NN = 5.02 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 μb-1 and 28 pb-1, respectively. The measurements are performed in the dimuon rapidity range of | y| < 2.4 as a function of centrality, rapidity, and transverse momentum (p_T) from p_T= 3 GeV/c in the most forward region and up to 50 GeV/c. Both prompt and nonprompt (coming from b hadron decays) J/ψ mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at √s_NN = 2.76 TeV for the two J/ψ meson components. No dependence on rapidity is observed for either prompt or nonprompt J/ψ mesons. An indication of a lower prompt J/ψ meson suppression at p_T> 25 GeV/c is seen with respect to that observed at intermediate p_T. The prompt ψ(2S) meson yield is found to be more suppressed than that of the prompt J/ψ mesons in the entire p_T range.
Measurement of prompt and nonprompt charmonium suppression in PbPb collisions at 5.02 TeV
Meridiani P.;Amapane N.;Argiro' S.;Bellan R.;Costa M.;Covarelli R.;Kiani B.;Migliore E.;Monaco V.;Monteil E.;Obertino M. M.;Pacher L.;Pinna Angioni G. L.;Romero A.;Sacchi R.;Sola V.;Solano A.;
2018-01-01
Abstract
The nuclear modification factors of J/ψ and ψ(2S) mesons are measured in PbPb collisions at a centre-of-mass energy per nucleon pair of √s_NN = 5.02 TeV. The analysis is based on PbPb and pp data samples collected by CMS at the LHC in 2015, corresponding to integrated luminosities of 464 μb-1 and 28 pb-1, respectively. The measurements are performed in the dimuon rapidity range of | y| < 2.4 as a function of centrality, rapidity, and transverse momentum (p_T) from p_T= 3 GeV/c in the most forward region and up to 50 GeV/c. Both prompt and nonprompt (coming from b hadron decays) J/ψ mesons are observed to be increasingly suppressed with centrality, with a magnitude similar to the one observed at √s_NN = 2.76 TeV for the two J/ψ meson components. No dependence on rapidity is observed for either prompt or nonprompt J/ψ mesons. An indication of a lower prompt J/ψ meson suppression at p_T> 25 GeV/c is seen with respect to that observed at intermediate p_T. The prompt ψ(2S) meson yield is found to be more suppressed than that of the prompt J/ψ mesons in the entire p_T range.File | Dimensione | Formato | |
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10.1140:epjc:s10052-018-5950-6.pdf
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