Performance and Improvements of the ATLAS jet trigger system

In 2011-2012 the Large Hadron Collider (LHC) provided proton bunch crossings every 50 ns with up to 40 interactions every crossing. These unprecedented conditions posed stringent demands on the trigger system of the ATLAS experiment, which must provide a fast rejection of background events while maintaining a high efficiency for physics signals of interest. This note focuses on the jet trigger system in ATLAS. Jets are the most prevalent high-PT objects produced at the LHC, and are an important component of a wide range of physics analyses. The challenges faced by the jet trigger system, and how its initial limitations were overcome, will be described. Performance results, including jet efficiency and resolution, will be presented.Peer Reviewe