${\cal O}(\alpha\alpha_s)$ corrections to the $\gamma t\bar{t}$ vertex at the top quark threshold

TL;DR

This paper calculates the final two-loop electroweak and QCD corrections to the gamma-top-antitop vertex at the top quark threshold, crucial for precise predictions of top quark production at electron-positron colliders.

Contribution

It provides the complete ${ m O}(\alphaeta_s)$ corrections to the gamma-top-antitop vertex, including the exchange of a W boson and a gluon, filling a key gap in theoretical predictions.

Findings

Complete two-loop corrections to the gamma t t̄ vertex at threshold.

Enhanced precision for top quark production cross section predictions.

Foundation for improved collider phenomenology analyses.

Abstract

We compute the last missing piece of the two-loop ${\cal O}(\alpha \alpha_s)$ corrections to $\gamma t \bar{t}$ vertex at the $t \bar{t}$ threshold due to the exchange of a $W$ boson and a gluon. This contribution constitutes a building block of the top quark threshold production cross section at electron positron colliders.