Performance of the CMS Level-1 Trigger during Commissioning with Cosmic Ray Muons

TL;DR

This paper evaluates the performance of the CMS Level-1 trigger system during cosmic ray and beam data runs in 2008, focusing on its components, algorithms, and efficiency in detecting muons, electrons, photons, and jets.

Contribution

It provides a detailed validation and performance assessment of the CMS Level-1 trigger system using cosmic ray data, including efficiency, resolution, and rate analysis.

Findings

High trigger efficiencies achieved

Good resolution of detected particles

Trigger rates matched expectations

Abstract

The CMS Level-1 trigger was used to select cosmic ray muons and LHC beam events during data-taking runs in 2008, and to estimate the level of detector noise. This paper describes the trigger components used, the algorithms that were executed, and the trigger synchronisation. Using data from extended cosmic ray runs, the muon, electron/photon, and jet triggers have been validated, and their performance evaluated. Efficiencies were found to be high, resolutions were found to be good, and rates as expected.