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 ����⎯⎯+ 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, m pole t , is: m=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.

Aad, G., Abbott, B., Abdallah, J., Abdel Khalek, S., Abdinov, O., Aben, R., et al. (2015). Determination of the top-quark pole mass using ttbar + 1-jet events collected with the ATLAS experiment in 7 TeV pp collisions. JOURNAL OF HIGH ENERGY PHYSICS, 2015(10) [10.1007/JHEP10(2015)121].

Determination of the top-quark pole mass using ttbar + 1-jet events collected with the ATLAS experiment in 7 TeV pp collisions

F. Ceradini;B. Di Micco;R. Di Nardo;D. Orestano;F. Petrucci;D. Puddu;G. Salamanna;