Suppression of non-prompt J/psi, prompt J/psi, and Y(1S) in PbPb collisions at sqrt(sNN) = 2.76 TeV

TL;DR

This paper reports measurements of J/psi and Y(1S) meson yields in PbPb and pp collisions at 2.76 TeV, revealing significant suppression patterns dependent on collision centrality and transverse momentum, indicating in-medium quark energy loss.

Contribution

It provides the first measurement of non-prompt J/psi suppression and detailed suppression patterns of quarkonium states in heavy-ion collisions at LHC energies.

Findings

Strong centrality-dependent suppression of prompt J/psi at high pt

First measurement of non-prompt J/psi suppression in PbPb collisions

Suppression of low-pt Y(1S) mesons in PbPb collisions

Abstract

Yields of prompt and non-prompt J/psi, as well as Y(1S) mesons, are measured by the CMS experiment via their dimuon decays in PbPb and pp collisions at sqrt(sNN) = 2.76 TeV for quarkonium rapidity |y|<2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum pt, as well as collision centrality. For prompt J/psi with relatively high pt (6.5<pt<30 GeV/c), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. In the same kinematic range, a suppression of non-prompt J/psi, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Also the low-pt Y(1S) mesons are suppressed in PbPb collisions.