2015/07/31 by ATLAS Collaboration · 1 citation
Physics and Astronomy · #hep-ex
paper · pdf · doi:10.1007/jhep10(2015)121
published as JHEP 10 (2015) 121 · 24 pages plus author list (40 pages total), 5 figures, 4 tables, published version, all figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2014-06/
arxiv created 2015/11/05 · arxiv updated 2015/11/06
The normalized differential cross section for top-quark pair production in association with at least one jet is studied as a function of the inverse of the invariant mass of the t t+1-jet system. This distribution can be used for a precise determination of the top-quark mass since gluon radiation depends on the mass of the quarks. The experimental analysis is based on proton-proton collision data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.6 fb-1. The selected events were identified using the lepton+jets top-quark-pair decay channel, where lepton refers to either an electron or a muon. The observed distribution is compared to a theoretical prediction at next-to-leading-order accuracy in quantum chromodynamics using the pole-mass scheme. With this method, the measured value of the top-quark pole mass, mt\rm pole, is: mt\rm pole =173.7 ± 1.5 (stat.) ± 1.4 (syst.) + 1.0-0.5 (theory) GeV. This result represents the most precise measurement of the top-quark pole mass to date.