May 25 – 30, 2020
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Measurement of the combined online and offline b-jet identification efficiency with ttbar events using a likelihood method in the ATLAS detector

May 28, 2020, 6:45 PM
Experimental poster Performance Poster Session (I)


Giovanni Bartolini (CPPM, Aix-Marseille Université, CNRS/IN2P3 (FR))


The identification of jets coming from the hadronization of b-quarks (b-tagging) is instrumental for many physics analyses performed at the Large Hadron Collider. ATLAS has b-tagging capability starting at trigger level, where b-tagging algorithms are fed with tracks that are reconstructed at the High-Level Trigger stage. Physics analyses with b-jets in the final state, but no lepton or missing transverse energy, benefit from using b-jet identification at trigger level in order to improve the signal efficiency. In Run 2, b-jet trigger efficiency is measured using a data sample enriched in ttbar di-leptonic events, employing a likelihood method. The b-tagging efficiency, for trigger algorithms as well as for the combination between trigger and offline algorithms, is extracted for jets in a transverse momentum range from 35 to 600 GeV, and data-to-simulation scale factors are derived.

Primary author

Giovanni Bartolini (CPPM, Aix-Marseille Université, CNRS/IN2P3 (FR))

Presentation materials