Determination of the top-quark pole mass and strong coupling constant from the tt¯ production cross section in pp collisions at s=7 TeV

Abstract

The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass, mt pole, or the strong coupling constant, αS. With the parton distribution function set NNPDF2.3, a pole mass of 176. 7+3.8 -3.4GeV is obtained when constraining αSat the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining mt poleto the latest average from direct mass measurements, a value of αS(mZ) = 0. 1151+0.0033 -0.0032is extracted. This is the first determination of αSusing events from top-quark production. © 2013 The Authors. Published by Elsevier B.V.