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. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.

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

P. Azzi;D. Bisello;A. Branca;R. Carlin;P. Checchia;M. Galanti;F. Gasparini;U. Gasparini;P. Giubilato;A. Gozzelino;S. Lacaprara;M. Margoni;A. T. Meneguzzo;J. Pazzini;N. Pozzobon;P. Ronchese;F. Simonetto;E. Torassa;M. Tosi;A. Triossi;P. Zotto;A. Zucchetta;G. Zumerle;M. Grassi;R. Rossin;A. Gaz;M. Zanetti;
2014

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. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2835536
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