Determination of the top-quark pole mass and strong coupling constant from the tt¯ production cross section in pp collisions at s=7 TeV
Determination of the top-quark pole mass and strong coupling constant from the tt¯ production cross section in pp collisions at s=7 TeV
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Date
2014-01-20
Authors
Chatrchyan, S.
Khachatryan, V.
Sirunyan, A. M.
Tumasyan, A.
Adam, W.
Bergauer, T.
Dragicevic, M.
Erö, J.
Fabjan, C.
Friedl, M.
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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, mtpole, 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 mtpole 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.
Description
Keywords
CMS,
Constant,
Coupling,
Cross section,
Mass,
Pair,
Physics,
QCD,
Quark,
Strong,
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Citation
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. v.728