Journal of High Energy Physics > 2018 > 2018 > 8 > 1-47
Measurements of b-jet tagging efficiency with the ATLAS detector using tt¯ $$ t\overline{t} $$ events at s=13 $$ \sqrt{s}=13 $$ TeV
Source
Abstract
The efficiency to identify jets containing b-hadrons (b-jets) is measured using a high purity sample of dileptonic top quark-antiquark pairs ( tt¯ $$ t\overline{t} $$) 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 $$ \sqrt{s}=13 $$ TeV. Two methods are used to extract the efficiency from tt¯ $$ t\overline{t} $$ 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.
Identifiers
journal e-ISSN : | 1029-8479 |
DOI | 10.1007/JHEP08(2018)089 |
Authors
The ATLAS collaboration
- University Politehnica Bucharest, Bucharest, Romania
- Centre National de l’Energie des Sciences Techniques Nucleaires (CNESTEN), Rabat, Morocco
- Universidade Nova de Lisboa, Dep Física and CEFITEC of Faculdade de Ciências e Tecnologia, Caparica, Portugal
- CERN, Geneva 23, Switzerland
B. Abbott
- University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, United States of America