NLO QCD corrections to Higgs boson production in association with a top quark pair and a jet

TL;DR

The paper delivers the first complete NLO QCD corrections to pp → tt̄H + j with full mass dependence, providing accurate total cross sections and differential distributions critical for probing the top-Higgs Yukawa coupling at the LHC. The authors introduce a novel integrand-reduction method via Laurent expansion implemented in Ninja, integrated with GoSam and Sherpa for an automated computation of virtual and real-emission contributions. They demonstrate a strong reduction of scale uncertainties at NLO and sizable corrections to key distributions, particularly in boosted Higgs regimes. The work validates the GoSam/Ninja+Sherpa framework for complex multi-leg processes with massive particles and enhances the reliability of simulations used in Higgs-top analyses.

Abstract

We present the calculation of the cross section for Higgs boson production in association with a top quark pair plus one jet, at next-to-leading-order (NLO) accuracy in QCD. All mass dependence is retained without recurring to any approximation. After including the complete NLO QCD corrections, we observe a strong reduction in the scale dependence of the result. We also show distributions for the invariant mass of the top quark pair, with and without the additional jet, and for the transverse momentum and the pseudorapidity of the Higgs boson. Results for the virtual contributions are obtained with a novel reduction approach based on integrand decomposition via Laurent expansion, as implemented in the library Ninja. Cross sections and differential distributions are obtained with an automated setup which combines the GoSam and Sherpa frameworks.

Figures (5)

• Figure 1: Sample of one-loop diagrams contributing to the NLO corrections to $g g \to t {\bar{t}} H g$ and $q {\bar{q}} \to t {\bar{t}} H g$.
• Figure 2:
• Figure 3: Invariant mass distributions of the $t\bar{t}$-pairs for $t \bar{t} H$ and $t \bar{t} H j$ at NLO relative to the $t \bar{t} H j$ at LO for $\mu=2\times\textrm{GA}_{T}$.
• Figure 4: Transverse momentum distribution of the Higgs boson at LO and NLO for $\mu=H_T$.
• Figure 5: Pseudorapidity $\eta$ of the Higgs boson at LO and NLO accuracy for $\mu=H_T$.