Abstract :
ATLAS is one of the general purpose detectors of the Large Hadron Collider (LHC) at CERN. The ATLAS trigger system, composed of three levels, is designed to cope with the LHC´s demanding requirements. There have been a lot of recent changes in the ATLAS jet trigger. The standard strategy, based on Regions Of Interest, is not well-suited for multi-jet events since it leads to pathologies and efficiency losses. This philosophy has been changed for the jet trigger, introducing the possibility of unpacking the full calorimeter at the Event Filter and (even for a small subset of the events) at Level-2. We also moved to the use of calibrated energy scale at the trigger level, and to the application of noise cuts to reduce rate spikes. We will present the performance of the jet trigger in 2011, when most of these changes were operational.
Keywords :
high energy physics instrumentation computing; transition radiation detectors; ATLAS jet trigger performance; ATLAS trigger system; Large Hadron Collider; event filter; jet trigger; multijet events; noise cut application; trigger level; Collaboration; Detectors; Electromagnetics; Large Hadron Collider; Noise; Physics; Poles and towers;
