Performance of CMS muon reconstruction from proton-proton to heavy ion collisions

TL;DR

This paper evaluates CMS muon reconstruction performance across different collision systems and energies, demonstrating high efficiency and stable momentum resolution even in high-occupancy heavy ion collisions.

Contribution

It provides a comprehensive comparison of muon reconstruction performance from proton-proton to heavy ion collisions at the CMS detector, highlighting stability across varying occupancy levels.

Findings

Muon efficiencies above 90% across most conditions

Momentum resolution and scale unaffected by occupancy

Consistent performance in high-multiplicity PbPb collisions

Abstract

The performance of muon tracking, identification, triggering, momentum resolution, and momentum scale has been studied with the CMS detector at the LHC using data collected at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV in proton-proton (pp) and lead-lead (PbPb) collisions in 2017 and 2018, respectively, and at $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV in proton-lead (pPb) collisions in 2016. Muon efficiencies, momentum resolutions, and momentum scales are compared by focusing on how the muon reconstruction performance varies from relatively small occupancy pp collisions to the larger occupancies of pPb collisions and, finally, to the highest track multiplicity PbPb collisions. We find the efficiencies of muon tracking, identification, and triggering to be above 90% throughout most of the track multiplicity range. The momentum resolution and scale are unaffected by the detector occupancy. The excellent muon reconstruction of the CMS detector enables precision studies across all available collision systems.