Commissioning of real time algorithms in the ATLAS tau trigger system

A significant part of the Standard Model particles involve tau leptons in their decay chains. For this reason it is very important to precisely measure the properties of taus. Given the fact, that the average decay length of the tau leptons is short (cτ = 87.11 μm), they can be studied only via their decay products, such as electrons, muons or pions. The ATLAS tau trigger system is dedicated to select tau decays involving hadrons, while rejecting a significant fraction of background events, such as QCD jets. In order to achieve this, a sophisticated three-level trigger system is used, which is tuned to be sensitive to the typical signature of taus: isolated narrow jets with low track multiplicity.