Configuration and performance of the ATLAS $b$-jet triggers in Run 2

Abstract

Several improvements to the ATLAS triggers used to identify jets containing $b$-hadrons ($b$-jets) were implemented for data-taking during Run 2 of the Large Hadron Collider from 2016 to 2018. These changes include reconfiguring the $b$-jet trigger software to improve primary-vertex finding and allow more stable running in conditions with high pile-up, and the implementation of the functionality needed to run sophisticated taggers used by the offline reconstruction in an online environment. These improvements yielded an order of magnitude better light-flavour jet rejection for the same $b$-jet identification efficiency compared to the performance in Run 1 (2011-2012). The efficiency to identify $b$-jets in the trigger, and the conditional efficiency for $b$-jets that satisfy offline $b$-tagging requirements to pass the trigger are also measured. Correction factors are derived to calibrate the $b$-tagging efficiency in simulation to match that observed in data. The associated systematic uncertainties are substantially smaller than in previous measurements. In addition, $b$-jet triggers were operated for the first time during heavy-ion data-taking, using dedicated triggers that were developed to identify semileptonic $b$-hadron decays by selecting events with geometrically overlapping muons and jets.

64 pages in total, author list starting page 48, 17 figures, 10 tables. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TRIG-2018-08

References in corpus (5)

• An Introduction to PYTHIA 8.2
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• Herwig++ Physics and Manual
• Glauber Modeling in High Energy Nuclear Collisions
• Parton distributions in the LHC era: MMHT 2014 PDFs

Cited by in corpus (14)

• A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
• The ATLAS Inner Detector Trigger performance in pp collisions at 13 TeV during LHC Run 2
• Search for nonresonant pair production of Higgs bosons in the $b\bar{b}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• The ATLAS Trigger System for LHC Run 3 and Trigger performance in 2022
• Search for resonant pair production of Higgs bosons in the $b\bar{b}b\bar{b}$ final state using $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Measurement of the nuclear modification factor of $b$-jets in 5.02 TeV Pb+Pb collisions with the ATLAS detector
• ATLAS searches for additional scalars and exotic Higgs boson decays with the LHC Run 2 dataset
• Constraints on spin-0 dark matter mediators and invisible Higgs decays using ATLAS 13 TeV $pp$ collision data with two top quarks and missing transverse momentum in the final state
• Fast $b$-tagging at the high-level trigger of the ATLAS experiment in LHC Run 3
• A search for triple Higgs boson production in the $6b$ final state using $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Combination of searches for resonant Higgs boson pair production using $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Search for pair production of higgsinos in events with two Higgs bosons and missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions at the ATLAS experiment
• Climbing to the Top of the ATLAS 13 TeV data
• Configuration, Performance, and Commissioning of the ATLAS $b$-jet Triggers for the 2022 and 2023 LHC data-taking periods