TY - JOUR

T1 - Measurements of b-jet tagging efficiency with the ATLAS detector using tt¯ events at √s=13 TeV

AU - Barton, Adam Edward

AU - Beattie, Michael

AU - Bertram, Iain Alexander

AU - Borissov, Guennadi

AU - Bouhova-Thacker, Evelina Vassileva

AU - Fox, Harald

AU - Henderson, Robert Charles William

AU - Jones, Roger William Lewis

AU - Kartvelishvili, Vakhtang

AU - Long, Robin Eamonn

AU - Love, Peter Allan

AU - Muenstermann, Daniel Matthias Alfred

AU - Parker, Adam Jackson

AU - Skinner, Malcolm

AU - Smizanska, Maria

AU - Tee, Amy

AU - Walder, James William

AU - Wharton, Andrew Mark

AU - Whitmore, Ben

AU - The ATLAS collaboration

PY - 2018/8/16

Y1 - 2018/8/16

N2 - The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs (tt¯) selected from the 36.1 fb−1 of data collected by the ATLAS detector in 2015 and 2016 from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy √s=13 TeV. Two methods are used to extract the efficiency from tt¯ events, a combinatorial likelihood approach and a tag-and-probe method. A boosted decision tree, not using b-tagging information, is used to select events in which two b-jets are present, which reduces the dominant uncertainty in the modelling of the flavour of the jets. The efficiency is extracted for jets in a transverse momentum range from 20 to 300 GeV, with data-to-simulation scale factors calculated by comparing the efficiency measured using collision data to that predicted by the simulation. The two methods give compatible results, and achieve a similar level of precision, measuring data-to-simulation scale factors close to unity with uncertainties ranging from 2% to 12% depending on the jet transverse momentum.

AB - The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs (tt¯) selected from the 36.1 fb−1 of data collected by the ATLAS detector in 2015 and 2016 from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy √s=13 TeV. Two methods are used to extract the efficiency from tt¯ events, a combinatorial likelihood approach and a tag-and-probe method. A boosted decision tree, not using b-tagging information, is used to select events in which two b-jets are present, which reduces the dominant uncertainty in the modelling of the flavour of the jets. The efficiency is extracted for jets in a transverse momentum range from 20 to 300 GeV, with data-to-simulation scale factors calculated by comparing the efficiency measured using collision data to that predicted by the simulation. The two methods give compatible results, and achieve a similar level of precision, measuring data-to-simulation scale factors close to unity with uncertainties ranging from 2% to 12% depending on the jet transverse momentum.

U2 - 10.1007/JHEP08(2018)089

DO - 10.1007/JHEP08(2018)089

M3 - Journal article

VL - 2018

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1029-8479

IS - 8

M1 - 89

ER -