The top quark right coupling in the tbW-vertex

Abstract

The most general parametrization of the $tbW$ vertex includes a right coupling $V_R$ that is zero at tree level in the standard model. This quantity may be measured at the Large Hadron Collider where the physics of the top decay is currently investigated. This coupling is present in new physics models at tree level and/or through radiative corrections, so its measurement can be sensitive to non standard physics. In this paper we compute the leading electroweak and QCD contributions to the top $V_R$ coupling in the standard model. This value is the starting point in order to separate the standard model effects and, then, search for new physics. We also propose observables that can be addressed at the LHC in order to measure this coupling. These observables are defined in such a way that they do not receive tree level contributions from the standard model and are directly proportional to the right coupling. Bounds on new physics models can be obtained through the measurements of these observables.

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Cited by in corpus (7)

• Measurement of the W boson helicity fractions in the decays of top quark pairs to lepton + jets final states produced in pp collisions at sqrt(s) = 8 TeV
• Probing anomalous $Wtb$ couplings at the LHC in single top quark production through $t$-channel
• Non-factorisable contribution to $t$-channel single-top production
• $tbW$ Anomalous Couplings in the Two Higgs Doublet Model
• Measurement of the polarisation of single top quarks and antiquarks produced in the $t$-channel at $\sqrt{s}=13$ TeV and bounds on the $tWb$ dipole operator from the ATLAS experiment
• The right top coupling in the aligned two-Higgs-doublet model
• Bread and butter physics: NLO electroweak corrections to polarized top quark decays