Performance of the ATLAS muon trigger in pp collisions at

The performance of the ATLAS muon trigger system is evaluated with proton–proton collision data collected in 2012 at the Large Hadron Collider at a centre-of-mass energy of 8 TeV. It is primarily evaluated using events containing a pair of muons from the decay of $$Z$$ bosons. The efficiency of the single-muon trigger is measured for muons with transverse momentum $$25 < p_\mathrm{{T}}< 100$$ GeV, with a statistical uncertainty of less than 0.01 % and a systematic uncertainty of 0.6 %. The $$p_\mathrm{{T}}$$ range for efficiency determination is extended by using muons from decays of $$J/\psi $$ mesons, $$W$$ bosons, and top quarks. The muon trigger shows highly uniform and stable performance. The performance is compared to the prediction of a detailed simulation