The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measure ments and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced back ground. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the AT LAS Collaboration, using TeV proton–proton collision data with an integrated luminosity of 140 fb col lected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is estab lished to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.

Aad, G., Abbott, B., Abeling, K., Abicht, N.j., Abidi, S.h., Aboulhorma, A., et al. (2024). Performance and calibration of quark/gluon-jet taggers using 140 fb−1 of pp collisions at TeV with the ATLAS detector. CHINESE PHYSICS C, 48(2) [10.1088/1674-1137/acf701].

Performance and calibration of quark/gluon-jet taggers using 140 fb−1 of pp collisions at TeV with the ATLAS detector

Aielli, G.;Camarri, P.;Cerrito, L.;De Sanctis, U.;Di Ciaccio, A.;