Performance of the ATLAS Trigger System in 2010

TLDR

The LHC operates at a 40 MHz bunch‑crossing rate, while the ATLAS trigger system records roughly 200 of these per second. The paper gives an overview of the ATLAS trigger system, its 2010 evolution and performance, and outlines plans for 2011. The trigger system selects events by rapidly identifying signatures of muons, electrons, photons, tau leptons, jets, B‑meson candidates, and global event signatures such as missing transverse energy. In 2010 the ATLAS trigger system recorded proton‑proton collisions at 7 TeV and heavy‑ion collisions at 2.76 TeV, demonstrating the performance of its components and selections.

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