Tau Lepton Reconstruction and ID with the ATLAS Detector at the LHC

Many models, among them light SM Higgs, SUSY Higgs at large tan(beta) and various other SUSY models, predict an abundant production of tau leptons. At the energy scale of the LHC, the identification of tau leptons, in particular in the hadronic decay mode, will pose a very challenging task due to an overwhelming QCD background. Nevertheless, exploiting the hadronic decays of the tau lepton allows for an increased signal efficiency by at least a factor of two in many cases, and provides an independent control sample to disentangle leptonic tau decays from prompt electrons and muons. Equipped with excellent tracking and calorimetry, the ATLAS experiment has developed tau identification tools capable of working already at the trigger level. In my talk will present the tau lepton reconstruction and identification methods developed by the ATLAS collaboration, both at the trigger and the offline levels. I will also show the ideas for the validation of the tau identification methods with the early data.