Eur. Phys. J. C (2014) 74: 3193
https://doi.org/10.1140/epjc/s10052-014-3193-8

Regular Article - Theoretical Physics

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

¹ INFN Trieste, Via Valerio 2, 34127 , Trieste, Italy
² INFN Trieste gruppo collegato di Udine and SISSA, Via Bonomea 265, 34136 , Trieste, Italy
³ ICTP-SAIFR and IFT UNESP, Rua Dr. Bento Teobaldo Ferraz 271, 01140-070 , São Paulo, Brazil

^* e-mail: alberto.tonero@gmail.com
^** e-mail: tonero@ift.unesp.br

Received: 22 August 2014
Accepted: 22 November 2014
Published online: 13 December 2014

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). For comparison, strongly interacting new physics is bounded by scales higher than 1.3 or 1.5 TeV (again depending on its contribution).