Higgs boson production in association with a top-antitop quark pair in next-to-next-to leading order QCD

Abstract

The associated production of a Higgs boson with a top-antitop quark pair is a crucial process at the LHC since it allows for a direct measurement of the top-quark Yukawa coupling. We present the computation of the radiative corrections to this process at the next-to-next-to-leading order (NNLO) in QCD perturbation theory. This is the very first computation for a $2 \to 3$ process with massive coloured particles at this perturbative order. We develop a soft Higgs boson approximation for loop amplitudes, which enables us to reliably quantify the impact of the yet unknown two-loop contribution. At the centre-of-mass energy $\sqrt{s}=13$ TeV the NNLO corrections increase the next-to-leading order result for the total cross section by about 4% and lead to a significant reduction of perturbative uncertainties.

Figures (1)

• Figure 1: LO, NLO and NNLO cross sections with their perturbative uncertainties as functions of the centre-of-mass energy. The experimental results from ATLAS ATLAS:2022vkf and CMS CMS:2022dwd at $\sqrt{s}=13$ TeV are also shown. The lower panel illustrates the impact of NNLO corrections with respect to the NLO result. The inner NNLO band denotes the uncertainty from the soft approximation combined with the systematic uncertainty from the subtraction procedure.