Electrons, photons and muons in ATLAS

ATLAS is a general purpose experiment which will operate at the LHC collider. In this paper, the detector performance in terms of electrons, photons and muons identification and measurements are presented, combining full GEANT simulation and test beam results. Some of the prominent methods and event samples which will be used in-situ to perform the calibration and evaluate the absolute energy scale are described as well. It is finally shown how these performances will allow ATLAS to accurately reconstruct signal mass peaks in several physics benchmark channels.