The ATLAS hadronic tau trigger

Abstract

With the high luminosities of proton-proton collisions achieved at the LHC, the strategies for triggering have become more important than ever for physics analysis. The naive inclusive single tau lepton triggers now suffer from severe rate limitations. To allow for a large program of physics analyses with taus, it is required that we combine tau signatures with other objects, including electrons, muons and missing transverse energy (MET). These combined triggers open many opportunities to study new physics beyond the Standard Model and to search for the Standard Model Higgs.We present the status and performance of the hadronic tau trigger in ATLAS. We explain how hadronic tau events are identified at trigger level using the ATLAS calorimeter and tracking system. Results from performance studies of the tau trigger are also shown, including measurements of the trigger efficiency using Z → ττ events.