Complete Next-to-Leading Order QCD Corrections to $ZZ$ Production in Gluon Fusion

TL;DR

This paper computes the full next-to-leading order QCD corrections to gluon fusion producing ZZ pairs, including top-quark mass effects, which are crucial for precise predictions at the LHC.

Contribution

It provides the first complete NLO QCD correction calculation for gg→ZZ including full top-quark mass effects, combining analytic and numerical methods.

Findings

Large NLO corrections to gg→ZZ production.

Destructive interference between massive top-quark and Higgs-mediated contributions.

Significant impact of NLO corrections on LHC ZZ production cross-section.

Abstract

We calculate the complete NLO QCD corrections to loop-induced $gg \rightarrow ZZ$ production including full top-quark mass effects. The two-loop virtual corrections are obtained by combining analytic results for the massless, Higgs-mediated, and one-loop factorizable contributions with numerically computed amplitudes containing the top-quark mass. We show that the choice of subtraction scheme for the virtual contribution impacts the precision with which the virtual contribution must be evaluated in order to obtain sufficiently precise phenomenological predictions. For direct production through a massive top-quark loop, we observe that the relative NLO corrections are large. The direct massive and Higgs-mediated contributions individually increase relative to the massless production at high diboson invariant mass, but interfere destructively with each other. At the Large Hadron Collider, the NLO corrections to the gluon channel give a sizable contribution to the $pp \to ZZ+X$ cross-section at N${}^3$LO.