Tau reconstruction and identification with 7 TeV collisions in ATLAS

The first LHC collisions at a centre-of-mass energy of sqrt{s}=7 TeV recorded with the ATLAS detector are used to study the reconstruction and identification algorithms for hadronic tau decays. Although the dataset used here, corresponding to an integrated luminosity of 244 nb-1, contains a small number of real tau leptons, the background jets reconstructed as tau candidates can be used to assess performance aspects of these algorithms.Distributions of identification variables are compared in data and Monte Carlo samples, and the background efficiency of cut-based tau identification criteria is measured in a QCD dijet enriched data sample. Good agreement is observed between data and the fake tau candidates selected from simulated QCD dijet events, giving confidence in the performance of the algorithms on real tau leptons, to be observed soon.