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

F. MONTICELLI; ATLAS COLLABORATION

JOURNAL OF HIGH ENERGY PHYSICS

SPRINGER

Lugar: Berlin; Año: 2015 vol. 1 p. 1 - 20

1126-6708

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 tt¯ + 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, mpolet , is: mpolet=173.7±1.5(stat.)±1.4(syst.)+1.0−0.5(theory)GeV.