We study the charge asymmetry between the t and t- quarks at the LHC, when they are produced in association with a W boson. Though sizably reducing the cross section with respect to the inclusive production, requiring a W boson in the final state has two important implications. First, at leading order in QCD, tt-W± production can only occur via qq- annihilation. As a result, the asymmetry between the t and t- generated at NLO in QCD is significantly larger than that of inclusive tt- production, which is dominated by gluon fusion. Second, the top quarks tend to inherit the polarization of the initial-state quarks as induced by the W-boson emission. Hence, the decay products of the top quarks display a sizable asymmetry already at the leading order in QCD. We study the relevant distributions and their uncertainties in the standard model, compare them to those obtained in a simple axigluon model and discuss prospects for measurements at the LHC and beyond. © 2014 The Authors. Published by Elsevier B.V.
Top-quark charge asymmetry and polarization in tt-W± production at the LHC / Maltoni, F.*; Mangano, M.L.; Tsinikos, I.; Zaro, M.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 736:(2014), pp. 252-260. [10.1016/j.physletb.2014.07.033]
Top-quark charge asymmetry and polarization in tt-W± production at the LHC
Maltoni, F.;
2014
Abstract
We study the charge asymmetry between the t and t- quarks at the LHC, when they are produced in association with a W boson. Though sizably reducing the cross section with respect to the inclusive production, requiring a W boson in the final state has two important implications. First, at leading order in QCD, tt-W± production can only occur via qq- annihilation. As a result, the asymmetry between the t and t- generated at NLO in QCD is significantly larger than that of inclusive tt- production, which is dominated by gluon fusion. Second, the top quarks tend to inherit the polarization of the initial-state quarks as induced by the W-boson emission. Hence, the decay products of the top quarks display a sizable asymmetry already at the leading order in QCD. We study the relevant distributions and their uncertainties in the standard model, compare them to those obtained in a simple axigluon model and discuss prospects for measurements at the LHC and beyond. © 2014 The Authors. Published by Elsevier B.V.File | Dimensione | Formato | |
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