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

Aad, G, Abbott, B, Abbott, DC, Abed Abud, A ORCID: 0000-0002-2788-3822, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H
et al (show 2836 more authors) (2021) Configuration and performance of the ATLAS b-jet triggers in Run 2. EUROPEAN PHYSICAL JOURNAL C, 81 (12). 1087-.

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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.

Item Type: Article
Additional Information: 61 pages in total, author list starting page 46, 17 figures, 10 tables, to be submitted to EPJC. All figures including auxiliary figures are available at
Uncontrolled Keywords: hep-ex, hep-ex
Divisions: Faculty of Science and Engineering > School of Physical Sciences
Depositing User: Symplectic Admin
Date Deposited: 10 Jan 2022 16:04
Last Modified: 18 Jan 2023 21:17
DOI: 10.1140/epjc/s10052-021-09775-5
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