Tau Trigger: Performance and Menus for Early Running

The selection of events with handronically decaying tau leptons is challenging due to high background rates at the LHC. On the other hand, efficient selection of events with tau leptons increases the discovery potential of ATLAS in many physics channels, notably Standard Model or Supersymmetric (SUSY) Higgs boson production. In this note we describe the ATLAS tau trigger system, focusing on the early data taking period, and present results from studies based on simulated events, including trigger rates and the acceptance of tau leptons from W and Z boson decays, Higgs Boson decays, and SUSY processes. In order to cope with the rate and optimize the efficiency of important physics channels, the results of the current simulation studies indicate that ATLAS tau triggers should include either relatively high transverse momentum single tau signatures, or low transverse momentum tau signatures in combination with other signatures, such as missing transverse energy, leptons, or jets.