The ATLAS hadronic tau trigger

Hadronic decay modes of the tau lepton play an important role in many searches for physics beyond the Standard Model (SM) as well as in SM measurements at the Large Hadron Collider (LHC). However, hadronic tau decays are difficult to identify and trigger on, due to their resemblance to QCD jets. Given the large production cross section of QCD processes, designing and operating a trigger system with the capability to efficiently select hadronic tau decays, while maintaining the rate within the bandwidth limits, is a difficult challenge. This paper summarises the status and performance of the ATLAS tau trigger system during the 2011 data taking period, and the upgrades put in place for the 2012 run.