English

Performance of the CMS high-level trigger during LHC Run 2

Instrumentation and Detectors 2024-11-26 v2 High Energy Physics - Experiment

Abstract

The CERN LHC provided proton and heavy ion collisions during its Run 2 operation period from 2015 to 2018. Proton-proton collisions reached a peak instantaneous luminosity of 2.1 ×\times 1034^{34} cm2^{-2}s1^{-1}, twice the initial design value, at s\sqrt{s} = 13 TeV. The CMS experiment records a subset of the collisions for further processing as part of its online selection of data for physics analyses, using a two-level trigger system: the Level-1 trigger, implemented in custom-designed electronics, and the high-level trigger, a streamlined version of the offline reconstruction software running on a large computer farm. This paper presents the performance of the CMS high-level trigger system during LHC Run 2 for physics objects, such as leptons, jets, and missing transverse momentum, which meet the broad needs of the CMS physics program and the challenge of the evolving LHC and detector conditions. Sophisticated algorithms that were originally used in offline reconstruction were deployed online. Highlights include a machine-learning b tagging algorithm and a reconstruction algorithm for tau leptons that decay hadronically.

Keywords

Cite

@article{arxiv.2410.17038,
  title  = {Performance of the CMS high-level trigger during LHC Run 2},
  author = {CMS Collaboration},
  journal= {arXiv preprint arXiv:2410.17038},
  year   = {2024}
}

Comments

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TRG-19-001 (CMS Public Pages)

R2 v1 2026-06-28T19:31:33.054Z