Aad, G.Abbott, B.Abbott, D.C.Abdinov, O.Abed Abud, A.Abeling, K.Abhayasinghe, D.K.Abidi, S.H.AbouZeid, O.SAbraham, N.L.Albert, JustinAnelli, Christopher R.Chiu, Y. H.Ghasemi Bostanabad, M.Hamano, KenjiHill, Ewan ChinKay, E. F.Keeler, RichardKowalewski, RobertLefebvre, Michelet al.2020-10-192020-10-1920192019Aad, G., Abbott, B., Abbott, D.C., Abdinov, O., Abed Abud, A., Abeling, K., … Zwalinski, L (2019). Measurement of the top-quark mass in tt + 1-jet events collected with the ATLAS detector in pp collisions at √s = 8 TeV. Journal of High Energy Physics, 2019(11) https://doi.org/10.1007/JHEP11(2019)150https://doi.org/10.1007/JHEP11(2019)150http://hdl.handle.net/1828/12213A determination of the top-quark mass is presented using 20.2 fb−1 of 8 TeV TeV proton-proton collision data produced by the Large Hadron Collider and collected by the ATLAS experiment. The normalised di erential cross section of top-quark pair production in association with an energetic jet is measured in the lepton+jets nal state and unfolded to parton and particle levels. The unfolded distribution at parton level can be described using next-to-leading-order QCD predictions in terms of either the top-quark pole mass or the running mass as de ned in the (modi ed) minimal subtraction scheme. A comparison between the experimental distribution and the theoretical prediction allows the top-quark mass to be extracted in the two schemes. The value obtained for the pole-mass scheme is: mpole t = 171:1 0:4 (stat) 0:9 (syst) +0:7 -0:3 (theo) GeV: The extracted value in the running-mass scheme is: mt(mt) = 162:9 0:5 (stat) 1:0 (syst) +2:1 -1:2 (theo) GeV: The results for the top-quark mass using the two schemes are consistent, when translated from one scheme to the other.enHadron-Hadron scattering (experiments), Top physicsArticleDepartment of Physics and Astronomy