Associated Top Quark-Higgs Boson Production at the LHC

TL;DR

This paper provides a precise SM prediction for associated top-quark–Higgs production at the LHC by calculating the ${\cal O}(\alpha_s^3)$ NLO QCD corrections to $pp\to t\bar{t}h$ at $\sqrt{s}=14$ TeV, including both virtual (pentagon-containing) and real emission contributions with robust cross-checks. The authors employ two phase-space slicing schemes to handle infrared singularities and validate the cutoff independence across all contributing channels, using contemporary PDFs. They find that NLO corrections raise the cross section by about 20–40% depending on the Higgs mass and scale choice, while dramatically reducing the renormalization/factorization scale uncertainty. The work strengthens the theoretical foundation for measuring the top Yukawa coupling and exploring new physics in the top sector, and provides a framework applicable to related processes such as $b\bar{b}h$ production.

Abstract

We compute the O(alpha_s^3) inclusive cross section for the process pp -> t-tbar-h in the Standard Model, at sqrt(s)=14 TeV. The next-to-leading order corrections drastically reduce the renormalization and factorization scale dependence of the Born cross section and increase the total cross section for renormalization and factorization scales larger than m_t. These corrections have important implications for models of new physics involving the top quark.

Figures (4)

• Figure 1: $\sigma_{ NLO}(pp\to t\bar{t}h)$ calculated in the two cutoff PSS approach when varying the soft cutoff $\delta_s$ in the range $10^{-5}$-$10^{-3}$, with the collinear cutoff set to $\delta_c\!=\!\delta_s/100$, at $\sqrt{s_{ H}}\!=\!14$ TeV, for $M_h\!=\!120$ GeV and $\mu\!=\!m_t$. The upper plot shows the cancellation of the $\delta_s,\delta_c$ dependence between $\sigma_{soft}+\sigma_{hard/coll}$ and $\sigma_{hard/non-coll}$. The lower plot shows the dependence of $\sigma_{ NLO}$ on $\delta_s,\delta_c$, with the corresponding statistical errors.
• Figure 2: Dependence of $\sigma_{ NLO}(pp \to t\bar{t}h)$ on the arbitrary cutoff $s_{min}$ of the one cutoff PSS method at $\sqrt{s_{ H}}\!=\!14$ TeV, for $M_h\!=\!120$ GeV and $\mu\!=\!m_t$. The upper plot shows the cancellation of the $s_{min}$ dependence between $\sigma_{ir}\!=\!\sigma_{ir}^c+ \sigma_{crossing}$, and $\sigma_{hard}$. The lower plot shows the dependence of $\sigma_{ NLO}$ on $s_{min}$, with the corresponding statistical errors.
• Figure 3: $\sigma_{ LO,NLO}(pp\to t\bar{t}h)$ as functions of the renormalization/factorization scale $\mu$, at $\sqrt{s_{ H}}\!=\!14$ TeV, for $M_h\!=\!120$ GeV.
• Figure 4: $\sigma_{ NLO}$ and $\sigma_{ LO}$ for $pp\to t\bar{t}h$ as functions of $M_h$, at $\sqrt{s_{H}}\!=\!14$ TeV, for $\mu\!=\!2m_t+M_h$.