Measurement of the top quark mass in the $t\overline{t}\to $ lepton+jets channel from $\sqrt{s}=8$ TeV ATLAS data and combination with previous results

The top quark mass is measured using a template method in the $t\overline{t}\to \mathrm{lepton}+\mathrm{jets}$ channel (lepton is e or $\mu $ ) using ATLAS data recorded in 2012 at the LHC. The data were taken at a proton–proton centre-of-mass energy of $\sqrt{s}=8$ $\text{TeV}$ and correspond to an integrated luminosity of $20.2$ fb ${}^{-1}$ . The $t\overline{t}\to \mathrm{lepton}+\mathrm{jets}$ 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 ${m}_{\mathrm{top}}=172.08\phantom{\rule{0.166667em}{0ex}}±\phantom{\rule{0.166667em}{0ex}}0.39\phantom{\rule{0.166667em}{0ex}}\left(\mathrm{stat}\right)\phantom{\rule{0.166667em}{0ex}}±\phantom{\rule{0.166667em}{0ex}}0.82\phantom{\rule{0.166667em}{0ex}}\left(\mathrm{syst}\right)$ $\text{GeV}$ . A combination with previous ATLAS ${m}_{\mathrm{top}}$ measurements gives ${m}_{\mathrm{top}}=172.69\phantom{\rule{0.166667em}{0ex}}±\phantom{\rule{0.166667em}{0ex}}0.25\phantom{\rule{0.166667em}{0ex}}\left(\mathrm{stat}\right)\phantom{\rule{0.166667em}{0ex}}±\phantom{\rule{0.166667em}{0ex}}0.41\phantom{\rule{0.166667em}{0ex}}\left(\mathrm{syst}\right)$ $\text{GeV}$ .