UC Santa Cruz

This paper presents the performance of the ATLAS muon reconstruction during the LHC run with pp$$pp$$ collisions at s=7$$\sqrt{s}=7$$–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/ψ→μμ$${J/\psi \rightarrow \mu \mu }$$, Z→μμ$$Z \rightarrow \mu \mu $$ and Υ→μμ$${\Upsilon \rightarrow \mu \mu }$$ 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 |η|<2.7$$|\eta |<2.7$$ and 5≲pT≲100$$5 \lesssim p_{\mathrm{T}}\lesssim 100$$ GeV) the efficiency is above 99%$$99\,\%$$ and is measured with per-mille precision. The momentum resolution ranges from 1.7%$$1.7\,\%$$ at central rapidity and for transverse momentum pT≃10$$p_{\mathrm{T}}\simeq 10$$ GeV, to 4%$$4\,\%$$ at large rapidity and pT≃100$$p_{\mathrm{T}}\simeq 100$$ GeV. The momentum scale is known with an uncertainty of 0.05%$$0.05\,\%$$ to 0.2%$$0.2\,\%$$ depending on rapidity. A method for the recovery of final state radiation from the muons is also presented.