Muon Performance in Minimum Bias pp Collision Data at √s = 7 TeV with ATLAS

Muonic final states provide clean signatures for many physics processes at the LHC. Up to transverse muon momenta of about 30 GeV muons are predominantly produced in weak decays of hadrons while they come from the decays of heavy particles at higher momenta. The design of the ATLAS detector allows for efficient muon identification with high resolution in a wide momentum range from the GeV to the TeV region. High momentum resolution and good rejection of muons from pion and kaon decays-in-flight are achieved by the combination of the precise momentum measurements in the inner detector and the ATLAS muon spectrometer. The measurement of the energy deposited around a muon in the calorimeters is used to select isolated muons. The performance of the ATLAS muon identification was studied with up to 0.5 nb−1 of LHC p p collision data at √s = 7 TeV collected with a minimum bias trigger. Measured detector efficiencies, hit multiplicities, and residual distributions of reconstructed muon tracks are well reproduced by the Monte-Carlo simulation.