NLO QCD corrections to the production of t-tbar-Z in gluon fusion

TL;DR

This paper calculates the next-to-leading order QCD corrections to the dominant gluon fusion process producing top-antitop-Z at the LHC, significantly refining cross section predictions for electroweak coupling measurements.

Contribution

It provides the first detailed NLO QCD correction calculation for gg -> t-tbar-Z, improving theoretical accuracy for this key process.

Findings

NLO corrections increase the cross section by up to 75%.

Residual scale dependence reduced to ±5%.

Enhances precision for top-quark electroweak coupling measurements.

Abstract

We compute the O(alpha_s) QCD corrections to the partonic process gg -> t-tbar-Z at the LHC. This partonic channel is the dominant component of the scattering process pp -> t-tbar-Z, which will be important for measuring the t-tbar-Z electroweak couplings. The O(alpha_s) corrections increase the total cross section by up to 75% for reasonable choices of the renormalization and factorization scales. Inclusion of these contributions descreases the residual scale dependence of the cross section coming from uncalculated higher order terms to +-5%.