Tracker and Calorimeter Performance for the Identification of Hadronic Tau Lepton Decays in ATLAS

Tau leptons play an important role in the physics program in ATLAS. They can be used not only in searches for new phenomena like the Higgs boson or Supersymmetry, or for electroweak measurements but also in detector related studies like the dete rmination of the missing transverse energy scale. Identifying hadronically decaying tau lepto ns requires good understanding of the detector performance, combining information from calorimeter and tracking detectors. The current status of the tau reconstruction and identification wit h the ATLAS detector is presented. The identification efficiencies are measured with W ! τν events, and found to be consistent with the prediction from Monte Carlo simulations.