Dimuon results in PbPb and pp collisions in CMS

TL;DR

This paper reviews CMS experiment results on dimuon production in PbPb and pp collisions at the LHC, highlighting quarkonium suppression and Z boson measurements as probes of hot QCD matter and initial state conditions.

Contribution

It presents the first measurements of quarkonium states and Z bosons in PbPb collisions at 2.76 TeV, demonstrating CMS's capabilities in high multiplicity environments.

Findings

Suppression of Upsilon excited states observed

CMS successfully measures primary and secondary J/psi

Z0 boson measurements provide initial state insights

Abstract

The LHC offers unique opportunities for studying the properties of hot QCD matter created in Pb+Pb collisions at extreme temperatures and very low parton momentum fractions. With its high precision, large acceptance for tracking and calorimetry, and a trigger scheme that allows analysis of each minimum bias Pb+Pb event, CMS is fully equipped to measure dimuons in the high multiplicity environment of Pb+Pb collisions. Such probes are especially relevant since they are produced at early times and propagate through the medium, mapping its evolution. The capabilities of the CMS experiment to study dimuon production in pp and Pb+Pb collisions based on the 2010 LHC runs will be reviewed. CMS is able to measure primary and secondary J/psi, as well as the three Upsilon states. Quarkonia results at sqrt(s)=2.76 TeV in pp and Pb+Pb will be presented, including a tantalizing observation of suppression of the Upsilon excited states. The Z0 boson inclusive and differential measurement as a probe of the initial state will be described.