TY - JOUR
T1 - Performance of electron and photon triggers in ATLAS during LHC Run 2
AU - Clark, Philip James
AU - Farrington, Sinead
AU - Faucci Giannelli, Michele
AU - Gao, Yanyan
AU - Hasib, Ahmed
AU - Leonidopoulos, Christos
AU - Martin, Victoria Jane
AU - Mijovic, Liza
AU - Wynne, Benjamin
AU - Collaboration, Atlas
PY - 2020/1/22
Y1 - 2020/1/22
N2 - 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$\times$10$^{34}$cm$^{-2}$s$^{-1}$, and a similar increase in the number of interactions per beam-crossing to about 60, trigger algorithms and selections were optimised to control the rates while retaining a high efficiency for physics analyses. For proton-proton collisions, the single-electron trigger efficiency relative to a single-electron offline selection is at least 75% for an offline electron of 31 GeV, and rises to 96% at 60 GeV; the trigger efficiency of a 25 GeV leg of the primary diphoton trigger relative to a tight offline photon selection is more than 96% for an offline photon of 30 GeV. For heavy-ion collisions, the primary electron and photon trigger efficiencies relative to the corresponding standard offline selections are at least 84% and 95%, respectively, at 5 GeV above the corresponding trigger threshold.
AB - Electron and photon triggers covering transverse energies from 5 GeV to several TeV are essential for the ATLAS experiment to record signals for a wide variety of physics: from Standard Model processes to searches for new phenomena in both proton-proton and heavy-ion collisions. To cope with a fourfold increase of peak LHC luminosity from 2015 to 2018 (Run 2), to 2.1$\times$10$^{34}$cm$^{-2}$s$^{-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.
U2 - 10.1140/epjc/s10052-019-7500-2
DO - 10.1140/epjc/s10052-019-7500-2
M3 - Article
SN - 1434-6044
VL - C80
JO - The European Physical Journal C
JF - The European Physical Journal C
IS - 1
M1 - 47
ER -