The top quark mass is measured using a template method in the tt¯→ lepton+jets channel (lepton is e or μ) using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton-proton centre-of-mass energy of √s=8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The tt¯→ lepton+jets channel is characterized by the presence of a charged lepton, a neutrino and four jets, two of which originate from bottom quarks (b). Exploiting a three-dimensional template technique, the top quark mass is determined together with a global jet energy scale factor and a relative b-to-light-jet energy scale factor. The mass of the top quark is measured to be mtop=172.08±0.39(stat)±0.82(syst) GeV. A combination with previous ATLAS mtop measurements gives mtop=172.69±0.25(stat)±0.41(syst) GeV.
Bibliographical note75 pages in total, author list starting page 59, 14 figures, 12 tables, submitted to EPJC. All figures including auxiliary figures are available at this http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2017-03