The inclusive cross section for top-quark pair production measured by the CMS experiment in protonâproton 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 176.7â3.4+3.8GeV is obtained when constraining αSat the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining mtpoleto the latest average from direct mass measurements, a value of αS(mZ)=0.1151â0.0032+0.0033is extracted. This is the first determination of αSusing events from top-quark production.
Determination of the top-quark pole mass and strong coupling constant from the tt¯ production cross section in pp collisions at s=7 TeV
Albergo, S.;Chiorboli, M.;Costa, S.;Giordano, F.;Potenza, R.;Tricomi, A.;Tuve, C.;
2014-01-01
Abstract
The inclusive cross section for top-quark pair production measured by the CMS experiment in protonâproton 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 176.7â3.4+3.8GeV is obtained when constraining αSat the scale of the Z boson mass, mZ, to the current world average. Alternatively, by constraining mtpoleto the latest average from direct mass measurements, a value of αS(mZ)=0.1151â0.0032+0.0033is extracted. This is the first determination of αSusing events from top-quark production.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.