$ZZ$ production at the LHC: NNLO predictions for $2\ell2\nu$ and $4\ell$ signatures

TL;DR

This paper presents the first NNLO QCD corrections for $ZZ$ production in all relevant leptonic decay channels at the LHC, improving theoretical precision and showing good agreement with experimental data.

Contribution

The work provides the first NNLO calculations for processes involving mixed diboson topologies and multiple leptonic final states, enhancing accuracy of theoretical predictions.

Findings

NNLO corrections significantly impact cross-section estimates.

Good agreement with ATLAS 8 TeV data.

Interference effects are negligible in most cases.

Abstract

We consider QCD radiative corrections to $ZZ$ production for all experimentally relevant leptonic processes. We report on a novel computation of next-to-next-to-leading-order (NNLO) corrections to the diboson signature with two charged leptons and missing transverse energy ($\ell\ell$+$E_T^{\rm miss}$). All relevant final states are considered: $\ell\ell\nu_\ell\nu_\ell$, $\ell\ell\nu_{\ell'}\nu_{\ell'}$ and $\ell\nu_{\ell}\ell'\nu_{\ell'}$. We also study processes with four charged leptons: $\ell\ell\ell\ell$ and $\ell\ell\ell'\ell'$. For the first time NNLO accuracy is achieved for a process mixing two double-resonant diboson topologies ($ZZ/W^+W^-\to\ell\ell\nu_\ell\nu_\ell$). We find good agreement with ATLAS data at 8 TeV. NNLO corrections are large (5-20% and more), and interference effects between $ZZ$ and $W^+W^-$ resonances turn out to be negligible in most cases.