Implementation and Performance of the ATLAS Jet Trigger

This work presents the challenges of the ATLAS jet trigger and describes its implementation and expected performance. The ATLAS trigger is organized in three levels: the first one (L1) is implemented in custom made electronic modules, while the High-Level Trigger (HLT) system, which groups the second (L2) and third (Event Filter, EF) trigger levels, is based on software running in commercial computers. Both L1 and the HLT perform reconstruction of physic objects, like leptons, photons or jets. A precise hadronic calibration is applied at the HLT with the aim of accurately determining the jet energy. This optimizes the behavior of our selection criteria. A dedicated calibration scheme is implemented at L2, while the EF uses offline algorithms. We discuss the strategies used to perform the hadronic calibration for the HLT. We review the current physics signatures, expected rates and efficiencies as obtained from MC studies.