Determination of the top-quark pole mass and strong coupling constant from the t t-bar production cross section in pp collisions at sqrt(s) = 7 TeV

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, View the MathML sourcemtpole, or the strong coupling constant, αSαS. With the parton distribution function set NNPDF2.3, a pole mass of View the MathML source176.7−3.4+3.8 GeV is obtained when constraining αSαS at the scale of the Z boson mass, mZmZ, to the current world average. Alternatively, by constraining View the MathML sourcemtpole to the latest average from direct mass measurements, a value of View the MathML sourceαS(mZ)=0.1151−0.0032+0.0033 is extracted. This is the first determination of αSαS using events from top-quark production.