Charmonium production measured in PbPb and pp collisions by CMS

TL;DR

This paper reports measurements of charmonium production in PbPb and pp collisions using CMS, focusing on the nuclear modification factor of prompt J/psi to study quark-gluon plasma effects.

Contribution

First measurement of the nuclear modification factor of prompt J/psi in PbPb collisions as a function of multiple variables by CMS.

Findings

Nuclear modification factor varies with transverse momentum and rapidity.

CMS can distinguish prompt from non-prompt J/psi in high-multiplicity environments.

Results provide insights into quark-gluon plasma properties.

Abstract

The Compact Muon Solenoid (CMS) is fully equipped to measure hard probes in the di-muon decay channel in the high multiplicity environment of nucleus-nucleus collisions. Such probes are especially relevant for studying the quark-gluon plasma since they are produced at early times and propagate through the medium, mapping its evolution. CMS is able to distinguish non-prompt from prompt J/psi in pp and PbPb collisions. We report here the nuclear modification factor of prompt J/psi in PbPb as a function of transverse momentum, rapidity, and the number of nucleons participating in the collision.