Performance of the ATLAS Trigger System in 2010

TL;DR

This paper evaluates the performance of the ATLAS trigger system during 2010 proton-proton and heavy ion collisions at the LHC, highlighting its capabilities in event selection and system evolution.

Contribution

It provides a comprehensive overview of the ATLAS trigger system's design, performance, and evolution during 2010, including analysis of trigger components and event selection efficiency.

Findings

Trigger system successfully recorded a subset of collision events at 200 Hz.

Performance metrics of trigger components meet design expectations.

System evolution improved event selection accuracy in 2010.

Abstract

Proton-proton collisions at sqrt{s} = 7 TeV and heavy ion collisions at sqrt{s_NN} = 2.76 TeV were produced by the LHC and recorded using the ATLAS experiment's trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented