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, m_t^pole, or the strong coupling constant, αS. With the parton distribution function set NNPDF2.3, a pole mass of 176.7−3.4+3.8 GeV is obtained when constraining αS at the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining m_t^pole to the latest average from direct mass measurements, a value of αS(mZ)=0.1151−0.0032+0.0033 is extracted. This is the first determination of αS using events from top-quark production.
Determination of the top-quark pole mass and strong coupling constant from the ttbar production cross section in pp collisions at sqrt(s) = 7 TeV
TOSI, SILVANO;
2014-01-01
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, m_t^pole, or the strong coupling constant, αS. With the parton distribution function set NNPDF2.3, a pole mass of 176.7−3.4+3.8 GeV is obtained when constraining αS at the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining m_t^pole to the latest average from direct mass measurements, a value of αS(mZ)=0.1151−0.0032+0.0033 is extracted. This is the first determination of αS using events from top-quark production.
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