The inclusive cross section for top-quark pair production measured by the CMS experiment in protonproton 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, alpha(S). With the parton distribution function set NNPDF2.3, a pole mass of 176.7(-3.4)(+3.8) GeV is obtained when constraining alpha(S) at the scale of the Z boson mass, m(Z), to the current world average. Alternatively, by constraining m(t)(pole) to the latest average from direct mass measurements, a value of alpha(S)(m(Z)) = 0.1151(-0.0032)(+0.0033) is extracted. This is the first determination of alpha(S) using events from top-quark production.

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

Sola, V;AMAPANE, Nicola Carlo;ARCIDIACONO, Roberta;ARGIRO', Stefano;BELLAN, Riccardo;CASASSO, STEFANO;COSTA, Marco;DEGANO, Alessandro;MIGLIORE, Ernesto;MONACO, Vincenzo;MONTEIL, ENNIO;MUSICH, MARCO;OBERTINO, Maria Margherita;ORTONA, GIACOMO;PACHER, LUCA;PELLICCIONI, Mario;POTENZA, ALBERTO;ROMERO, Alessandra;SACCHI, Roberto;SOLANO, Ada Maria;TAMPONI, UMBERTO;COVARELLI, Roberto;
2014-01-01

Abstract

The inclusive cross section for top-quark pair production measured by the CMS experiment in protonproton 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, alpha(S). With the parton distribution function set NNPDF2.3, a pole mass of 176.7(-3.4)(+3.8) GeV is obtained when constraining alpha(S) at the scale of the Z boson mass, m(Z), to the current world average. Alternatively, by constraining m(t)(pole) to the latest average from direct mass measurements, a value of alpha(S)(m(Z)) = 0.1151(-0.0032)(+0.0033) is extracted. This is the first determination of alpha(S) using events from top-quark production.
2014
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Chatrchyan, S; Khachatryan, V; Sirunyan, Am; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Ero, J; Fabjan, C; Friedl, M; Fruhwirth, R; Ghete, Vm; ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/156060
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