Direct top-quark decay width measurement in the $t\bar{t}$ lepton+jets channel at $\sqrt{s}$=8 TeV with the ATLAS experiment

Abstract

This paper presents a direct measurement of the decay width of the top quark using $t\bar{t}$ events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb${}^{-1}$. The decay width of the top quark is measured using a template fit to distributions of kinematic observables associated with the hadronically and semileptonically decaying top quarks. The result, ${\Gamma }_t=1.76\pm 0.33(stat.{)}_{-0.68}^{+0.79}(syst.)\mathrm{GeV}$ for a top-quark mass of 172.5 GeV, is consistent with the prediction of the Standard Model.

arXiv comment44 pages in total, author list starting page 28, 6 figures, 3 tables, published in EPJC, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2017-02/

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