QCD corrections to ZZ production in gluon fusion at the LHC

TL;DR

This paper calculates next-to-leading order QCD corrections to gluon fusion producing Z-boson pairs at the LHC, revealing significant enhancements that impact total Z-pair production predictions.

Contribution

It provides the first detailed NLO QCD correction calculation for the loop-induced gg → ZZ process, highlighting its potential dominance in higher-order contributions.

Findings

QCD corrections increase gg → ZZ cross section by 50-100%

The corrections lead to a 6-8% increase in total pp → ZZ cross section

Corrections surpass previous theoretical uncertainty estimates

Abstract

We compute the next-to-leading order QCD corrections to the production of two Z-bosons in the annihilation of two gluons at the LHC. Being enhanced by a large gluon flux, these corrections provide distinct and, potentially, the dominant part of the N$^3$LO QCD contributions to Z-pair production in proton collisions. The $gg \to ZZ$ annihilation is a loop-induced process that receives the dominant contribution from loops of five light quarks, that are included in our computation in the massless approximation. We find that QCD corrections increase the $gg \to ZZ$ production cross section by ${\cal O}(50\%-100\%)$ depending on the values of the renormalization and factorization scales used in the leading order computation, and the collider energy. The large corrections to $gg \to ZZ$ channel increase the $pp \to ZZ$ cross section by about six to eight percent, exceeding the estimated theoretical uncertainty of the recent NNLO QCD calculation.