The ATLAS Detector: Performance Results

The ATLAS experiment is designed to study the proton-proton collisions produced at the Large Hadron Collider (LHC) at CERN. During Run I data taking, the ATLAS trigger system has been used to collect a rich data sample which supports a wide variety of physics analyses. The 2012 run saw larger luminosities and pile-up than 2011, which placed large demands on both the trigger system and analyses. The efficient reconstruction and identification of the different leptons, (b)-jets and missing transverse energy played a key role in the different analyses, specially in the discovery of the Higgs boson announced in 2012. This talk reports about efficiency, resolution, and general performance of the ATLAS detector by using mainly proton-proton collision data at sqrt(s)=8 TeV collected in year 2012.