LAUSR

We examine the effect of higher-order QCD corrections on the four top-quark production cross section in the 3 lepton decay channel. Top-quark and W gauge-boson decays are included at next-to-leading order in perturbative QCD. The narrow-width approximation, that preserves spin correlations, is used to perform the calculation for this complex 2 → 12 (13) process. We present differential cross-section distributions of top-quark decay products for the LHC Run III energy of s\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \sqrt{s} $$\end{document} = 13.6 TeV, using realistic selection cuts. Our results show that QCD corrections and jet radiation in top-quark and W decays can lead to significant changes in shapes of basic kinematic distributions and, therefore, need to be included for the accurate description of pp → tt¯tt¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ t\overline{t}t\overline{t} $$\end{document} + X process in the 3ℓ decay channel. The NLO QCD results obtained in this work are important in the context of the recent observation of the pp → tt¯tt¯\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ t\overline{t}t\overline{t} $$\end{document} + X process by the ATLAS and CMS collaborations and are of great significance for the High-Luminosity phase of the LHC.