Non-QCD contributions to top-pair production near threshold

TL;DR

This paper examines non-QCD effects, including electroweak and Higgs contributions, on top-pair production near threshold at future lepton colliders, enhancing the precision of Standard Model parameter measurements.

Contribution

It provides a detailed analysis of non-QCD effects at higher orders, extending the understanding of top-pair production near threshold beyond pure QCD corrections.

Findings

Non-QCD effects significantly influence the top-pair production cross section.

Electroweak and Higgs contributions affect the sensitivity to top quark parameters.

Higher-order corrections improve the accuracy of top quark property determinations.

Abstract

The threshold scan of top pair production at a future lepton collider allows to determine several Standard Model parameters with very high precision. The recent completion of the third-order QCD corrections to the inclusive top-pair production cross section demonstrated that strong dynamics are under control. We investigate effects from P-wave production and Higgs contributions at third order and from QED and the nonresonant production of the physical $W^+W^-b\bar{b}$ final state at first order. We discuss the sensitivity of the cross section to the top mass, width and Yukawa coupling as well as to the strong coupling.