Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data

TL;DR

This paper evaluates the performance of the ATLAS detector's muon reconstruction during 2011-2012 LHC runs, demonstrating high efficiency, precise momentum measurements, and providing corrections for physics analyses.

Contribution

It provides detailed measurements of muon reconstruction efficiency, momentum scale, and resolution, along with correction methods, based on large collision data samples.

Findings

Muon reconstruction efficiency exceeds 99% in most of the phase space.

Momentum resolution varies from 1.7% to 4% depending on rapidity and transverse momentum.

Momentum scale uncertainty is between 0.05% and 0.2%.

Abstract

This paper presents the performance of the ATLAS muon reconstruction during the LHC run with $pp$ collisions at $\sqrt{s}=7-8$ TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements of the reconstruction efficiency and of the momentum scale and resolution, based on large reference samples of $J/\psi\to \mu\mu$, $Z\to \mu\mu$ and $\Upsilon\to\mu\mu$ decays, are presented and compared to Monte Carlo simulations. Corrections to the simulation, to be used in physics analysis, are provided. Over most of the covered phase space (muon $|\eta|<2.7$ and $5 \lesssim p_{\mathrm{T}} \lesssim 100$ GeV) the efficiency is above $99\%$ and is measured with per-mille precision. The momentum resolution ranges from $1.7\%$ at central rapidity and for transverse momentum $p_{\mathrm{T}} \simeq 10$ GeV, to $4\%$ at large rapidity and $p_{\mathrm{T}} \simeq 100$ GeV. The momentum scale is known with an uncertainty of $0.05\%$ to $0.2\%$ depending on rapidity. A method for the recovery of final state radiation from the muons is also presented.