Weak Interactions in Top-Quark Pair Production at Hadron Colliders: An Update

TL;DR

This paper revisits weak corrections in top-quark pair production at hadron colliders, highlighting their significance in certain kinematic regions and proposing methods for their implementation in simulations to improve theoretical predictions.

Contribution

It provides updated predictions for weak corrections at LHC energies, identifies regions with large corrections, and offers a practical prescription for incorporating these effects into Monte Carlo generators.

Findings

Weak corrections become significant at high momentum transfer regions.

Threshold region analysis constrains the top-quark Yukawa coupling.

Weak corrections can be implemented in existing Monte Carlo tools.

Abstract

Weak corrections for top-quark pair production at hadron colliders are revisited. Predictions for collider energies of 8 TeV, adopted to the recent LHC run, and for 13 as well as 14 TeV, presumably relevant for the next round of LHC experiments, are presented. Kinematic regions with large momentum transfer are identified, where the corrections become large and may lead to strong distortions of differential distributions, thus mimicking anomalous top quark couplings. As a complementary case we investigate the threshold region, corresponding to configurations with small relative velocity between top and antitop quark, which is particularly sensitive to the top-quark Yukawa coupling. We demonstrate, that nontrivial upper limits on this coupling, complementary to those recently derived by the CMS and the ATLAS collaorations, are well within reach of ongoing experiments. In addition we suggest a prescription that allows the implementation of these corrections in current Monte Carlo generators. Furthermore, the weak corrections have been included in the publicly available Hathor library. The numerical results presented in this article use the same setup as the recently calculated NNLO QCD corrections. The results can thus be combined to give the most precise theoretical predictions.