Higgs-Pair Production via Gluon Fusion: Top-Yukawa- and light-quark-induced electroweak Corrections

TL;DR

This paper addresses the need for precise theory predictions for Higgs pair production via gluon fusion at the HL-LHC by computing the full electroweak corrections induced by top Yukawa and light-quark loops. The authors implement a numerical framework that projects onto the two LO spin-0 form factors, uses Feynman parametrization and end-point subtractions for two-loop diagrams, and employs complex masses with Richardson extrapolation to reach the narrow-width limit. They find total electroweak corrections of about -3.4% to the hadronic cross section, with the top-Yukawa part around -1.9% and the light-quark part around -1.5%; large invariant Higgs pair masses and threshold regions show larger effects. The results provide a transparent decomposition of diagram classes and a stepping stone toward complete electroweak corrections to gg→HH, enabling improved HL-LHC precision for the Higgs self-coupling.

Abstract

Gluon fusion, $gg\to HH$, is the dominant Higgs-pair production process at the Large Hadron Collider (LHC) and provides the first direct access to the trilinear Higgs self-interaction. The process is loop-induced, with the main contribution emerging from top-quark loops within the Standard Model. In the past, the QCD corrections have been calculated and found to increase the cross section significantly. With the anticipated accuracies achievable at the high-luminosity LHC (HL--LHC), the theoretical uncertainties will be of increased relevance to compete with the experimental precision at the level of less than 30\%. In this work, we take the next steps towards the determination of the complete electroweak corrections at next-to-leading order by calculating the full top-Yukawa and light-quark induced corrections. These corrections modify the cross section moderately in the kinematical regimes of interest.

Figures (11)

• Figure 1: Typical diagrams of Higgs-boson pair production via gluon fusion at LO. The contribution of the trilinear Higgs coupling is marked in red.
• Figure 2: Two-loop triangle diagrams of the top-Yukawa-induced electroweak corrections to Higgs-boson pair production involving Higgs $H$ and Goldstone $G^0,G^\pm$ exchanges. The bottom propagators only contribute to the diagrams with charged Goldstone exchange.
• Figure 3: Example of a two-loop tadpole diagram of the top-Yukawa induced electroweak corrections to Higgs-boson pair production involving Higgs exchange. Goldstone exchange does not contribute to the tadpoles.
• Figure 4: The relative top-Yukawa-induced electroweak correction factor $\delta_1$ as a function of the invariant Higgs-pair mass $M_{HH}$ with the top-Yukawa factor $x_t$ stripped off. The dots along the curves represent the numerical numbers we generated. The dotted curve shows the HTL of the full result, $C_1\to 1/2$ for large values of $m_t$.
• Figure 5: Sample two-loop box diagrams of the top-Yukawa-induced electroweak corrections to Higgs-boson pair production involving Higgs $H$ and Goldstone $G^0,G^\pm$ exchanges. The bottom propagators only contribute to the diagrams with charged Goldstone exchange.