Performance of the ATLAS tau trigger in 2011

This note describes the optimization and performance of the ATLAS hadronic tau trigger during 2011, at a centre-of-mass energy of 7 TeV. The selection criteria at every trigger level are optimized taking into account the increased number of overlapping interactions during the year. The evolution of the tau trigger configuration as a function of luminosity is described and trigger rates for various tau trigger selections are presented. The performance of tau triggers with various thresholds and selection requirements has been evaluated in data and compared to the expectations from Monte Carlo simulation. Simulated samples for various physics processes, including Z → ττ, di-jets and W → τν, have been used to measure trigger efficiencies.