Performance of electron and photon triggers in ATLAS during LHC Run 2
Abstract
Electron and photon triggers covering transverse energies from 5 GeV to several TeV are essential for the ATLAS experiment to record signals for a wide variety of physics: from Standard Model processes to searches for new phenomena in both proton-proton and heavy-ion collisions. To cope with a fourfold increase of peak LHC luminosity from 2015 to 2018 (Run 2), to 2.1 ×1034cm-2s-1 , and a similar increase in the number of interactions per beam-crossing to about 60, trigger algorithms and selections were optimised to control the rates while retaining a high efficiency for physics analyses. For proton-proton collisions, the single-electron trigger efficiency relative to a single-electron offline selection is at least 75% for an offline electron of 31 GeV , and rises to 96% at 60 GeV ; the trigger efficiency of a 25 GeV leg of the primary diphoton trigger relative to a tight offline photon selection is more than 96% for an offline photon of 30 GeV . For heavy-ion collisions, the primary electron and photon trigger efficiencies relative to the corresponding standard offline selections are at least 84% and 95%, respectively, at 5 GeV above the corresponding trigger threshold.
- Publication:
-
European Physical Journal C
- Pub Date:
- January 2020
- DOI:
- 10.1140/epjc/s10052-019-7500-2
- arXiv:
- arXiv:1909.00761
- Bibcode:
- 2020EPJC...80...47A
- Keywords:
-
- High Energy Physics - Experiment
- E-Print:
- 56 pages in total, author list starting page 40, 26 figures, 10 tables, published in EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TRIG-2018-05