Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

TL;DR

This paper evaluates the CMS detector's muon reconstruction, identification, and triggering performance in 7 TeV proton-proton collisions, demonstrating high efficiency, low misidentification, and precise momentum measurement consistent with simulations.

Contribution

It provides a comprehensive assessment of muon performance metrics in CMS at 7 TeV, including efficiencies, resolutions, and scale calibration, using early LHC data.

Findings

Muon reconstruction efficiency >95% for pT > a few GeV

Misidentification probability below 1%

Momentum resolution up to 6% depending on eta

Abstract

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.