Limits on anomalous top-quark gauge couplings from Tevatron and LHC data

Abstract

We review and update current limits on possible anomalous couplings of the top quark to gauge bosons. We consider data from top quark decay (as encoded in the W-boson helicity fractions) and single-top production (in the t-, s-and Wt-channels). We find improved limits with respect to previous results (inmost cases of almost one order of magnitude) and extend the analysis to include four-quark operators. We find that new electroweak physics is constrained to live above an energy scale between 430 GeV and 3.2 TeV (depending on the form of its contribution). For comparison, strongly interacting new physics is bounded by scales higher than 1.3 or 1.5 TeV (again depending on its contribution).