Reconstruction and Identification of Hadronically Decaying Tau Leptons at ATLAS

Tau leptons play an important role in the physics program at the LHC. They are used not only in searches for new phenomena like the Higgs boson or Supersymmetry and electroweak measure- ments, but also in detector related studies like the determination of the missing transverse energy scale. Variables describing the properties of calorimeter energy deposits and track reconstruc- tion within tau candidates are combined in multi-variate discriminants to achieve high rejection against backgrounds. The identification efficiencies are measured by W → τ ν and Z → τ τ events, and compared with the prediction of the Monte Carlo simulation. The energy scale uncertainties for tau leptons are determined by investigating single hadron calorimeter response, as well as kinematic distributions in Z → ττ events.