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

TL;DR

This paper reviews and updates constraints on anomalous top quark gauge couplings using Tevatron and LHC data, significantly improving previous limits and exploring effects of four-quark operators, thereby constraining new physics scales.

Contribution

It provides the most recent and tighter bounds on anomalous top couplings, including four-quark operators, and extends the analysis to new physics energy scales.

Findings

Electroweak new physics constrained above 430 GeV to 3.2 TeV.

Strongly interacting new physics bounded above 1.3-1.5 TeV.

Improved limits by nearly an order of magnitude over previous results.

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 (in most 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); strongly interacting new physics is bounded by scales higher than 1.3 or 1.5 TeV (again depending on its contribution).