$t\bar{t}t\bar{t}$: NLO QCD corrections in production and decays for the $3\ell$ channel

We discuss the results for the four-top quark production process at the LHC at NLO accuracy in perturbative QCD for the 3\ell 3 ℓ decay channel. The QCD corrections are applied in both the production and the decay stages of the four top quarks by employing the narrow-width approximation. The spin correlations are therefore preserved at NLO accuracy in QCD without any approximation. We summarize the impact of higher-order QCD effects by highlighting the sensitivity of the results on the cut applied on the invariant mass of the two hardest light jets in the process.