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Compact Muon Solenoid
LHC, CERN

CMS-PAS-HIN-24-001
Observation of the multiplicity dependence of σψ(2S)/σJ/ψ in pPb collisions at 8.16 TeV
Abstract: The ratio of ψ(2S) and J/ψ meson production cross sections is measured as a function of the charged-particle multiplicity in pPb collisions at center-of-mass energy per nucleon pair of sNN= 8.16 TeV using the CMS detector. The data corresponds to an integrated luminosity of 175 nb1. Both charmonium states are measured using the dimuon decay channel. The ratio is measured for both prompt and nonprompt ψ(2S) and J/ψ mesons separately. A multiplicity-dependent modification of the ratio is observed for prompt mesons. The ratio of the nonprompt ψ(2S) to J/ψ cross sections show no dependency on multiplicity. No significant rapidity-dependence is observed within the charmonium rapidity range 2.865 <yCM< 1.935 and transverse momentum range probed, 3 <pT< 30 GeV. These measurements constrain hadronization models of heavy quarks in nuclear collisions and support a picture in which co-moving particles may preferentially dissociate weakly-bound charmonia excited states as compared to the ground state during the evolution of the system.
CMS Publications
Compact Muon Solenoid
LHC, CERN