Implementation and Performance of the ATLAS Jet Trigger

The ATLAS trigger is organized in three levels: the first one (LVL1) is hardware based, while the High-Level Trigger (HLT) system, which groups the second (LVL2) and third (Event Filter, EF) trigger levels, is software based. The ATLAS jet trigger must accurately measure the jet energy, to distinguish high pT jets from low pT ones. Hadronic calibration is applied at HLT: a dedicated calibration scheme is implemented at LVL2, while the EF uses offline algorithms. This poster presents the challenges of the ATLAS jet trigger and describes its implementation and expected performance. We review the current physics signatures, expected rates and efficiencies as obtained from MC studies. We discuss the strategies used to perform the hadronic calibration for the HLT.