Four top final states with NLO accuracy in perturbative QCD: 4 lepton channel

TL;DR

This paper presents the calculation of next-to-leading order QCD corrections for four top-quark production in the four-lepton decay channel at the LHC, including decay effects and theoretical uncertainties.

Contribution

It provides the first NLO QCD predictions for four top-quark production in the 4-lepton channel with decay effects and uncertainty analysis.

Findings

NLO corrections increase the predicted cross sections.

Results are provided for different PDF sets and scale choices.

The study assesses theoretical uncertainties in the predictions.

Abstract

Triggered by the observation of four top-quark production at the LHC by the ATLAS and CMS collaboration we report on the calculation of the next-to-leading order QCD corrections to the Standard Model process $pp \to t\bar{t}t\bar{t}$ in the $4\ell$ top-quark decay channel. We take into account higher-order QCD effects in both the production and decays of the four top quarks. The latter effects are treated in the narrow width approximation, which preserves top-quark spin correlations throughout the calculation. We present results for two selected renormalisation and factorisation scale settings and three different PDF sets. Furthermore, we study the main theoretical uncertainties that are associated with the neglected higher-order terms in the perturbative expansion and with the parameterisation of the PDF sets. The results at the integrated and differential fiducial cross-section level are shown for the LHC Run III center-of-mass energy of $\sqrt{s}=13.6$ TeV. Our findings are particularly relevant for precise measurements of the four top-quark fiducial cross sections and for the modelling of top-quark decays at the LHC.