Four top final states with NLO accuracy in perturbative QCD: 3 lepton channel

A bstract 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 $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 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 → $$ t\overline{t}t\overline{t} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> + X process in the 3 ℓ decay channel. The NLO QCD results obtained in this work are important in the context of the recent observation of the pp → $$ t\overline{t}t\overline{t} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> + X process by the ATLAS and CMS collaborations and are of great significance for the High-Luminosity phase of the LHC.