Performance of electron and photon triggers in ATLAS during LHC Run 2

F. MONTICELLI; ATLAS CLLABORATION

EUROPEAN PHYSICAL JOURNAL C - PARTICLES AND FIELDS

SPRINGER

Lugar: Berlin; Año: 2020

1434-6044

Electron and photon triggers covering transverse energies from 5 GeV to several TeV areessential for the ATLAS experiment to record signals for a wide variety of physics: fromStandard Model processes to searches for new phenomena in both proton?proton and heavy-ioncollisions. To cope with a fourfold increase of peak LHC luminosity from 2015 to 2018 (Run 2),to 2.1×1034 cm−2 s−1 , and a similar increase in the number of interactions per beam-crossing toabout 60, trigger algorithms and selections were optimised to control the rates while retaininga high efficiency for physics analyses. For proton?proton collisions, the single-electrontrigger efficiency relative to a single-electron offline selection is at least 75% for an offlineelectron of 31 GeV, and rises to 96% at 60 GeV; the trigger efficiency of a 25 GeV leg of theprimary diphoton trigger relative to a tight offline photon selection is more than 96% for anoffline photon of 30 GeV. For heavy-ion collisions, the primary electron and photon triggerefficiencies relative to the corresponding standard offline selections are at least 84% and 95%,respectively, at 5 GeV above the corresponding trigger threshold.