Determination of the misidentification rate of hadronically decaying tau leptons using Z->ee+ jet events with ATLAS

In searches for the Higgs boson and physics beyond the Standard Model, the presence of tau leptons in the final state is an important signature at the ATLAS detector of the Large Hadron Collider. Hadronically decaying tau leptons can be reconstructed and identified over a broad kinematic range. Their signature in the detector is similar to other processes involving hadronic interactions. Therefore it is important to determine the misidentified tau lepton candidates in the detector. An identification method use cuts based on calorimeter variables, which are presumed to be well understood for the first data. In this thesis a method is described, to estimate the number of misidentified hadronically decaying tau leptons candidates caused by QCD dijet background events using Z->ee+jet events.