The ATLAS Muon Trigger Performance in pp collisions at $\sqrt s$ = 8 TeV

Events with muons in the final state are an important signature for many physics topics at the Large Hadron Collider (LHC), for instance searches for muonic Higgs boson decays or new phenomena, or measurements of the standard model (SM) processes like top-quark, W-boson, and Z-boson production. The use of efficient trigger muon selections during data taking and a good understanding of their performance is crucial for these physics studies. At the LHC high rejection power against the large SM backgrounds, while simulatneously maintaining high efficiency for rare signal events, is required at the online trigger stage. The ATLAS experiment employs a multi-level trigger architecture that selects the events in three sequential steps of increasing complexity and accuracy to cope with this challenging task. This presentation reports about efficiency, resolution, and general performance of the ATLAS muon trigger for proton-proton collision data at $\sqrt s$ = 8TeV collected in year 2012.