Higgs boson pair production in new physics models at hadron, lepton, and photon colliders

TL;DR

This work scrutinizes Higgs boson pair production at hadron, lepton, and photon colliders as a probe of the Higgs potential, focusing on how the one-loop corrected triple-Higgs coupling $\lambda_{hhh}$ and additional loop contributions from new particles modify cross sections. It analyzes four new-physics scenarios—THDM, scalar leptoquarks, chiral fourth generation, and vectorlike quarks—highlighting nondecoupling effects that can yield large, model-dependent shifts in $gg\to hh$, $e^+e^-\to hhZ$, $e^+e^-\to hh\nu\bar{\nu}$, and $\gamma\gamma\to hh$ across different collider energies. The study finds that nondecoupling bosonic loops can significantly amplify $\lambda_{hhh}$ and related cross sections (up to ~$+\!100$\% or more in some models), while fermionic loops can either enhance or suppress depending on interference and precision constraints; vectorlike quarks typically yield modest effects due to decoupling. These complementary measurements across collider modes can distinguish whether new physics particles in the loops are colored or electrically charged, fermions or bosons, and thereby illuminate the underlying Higgs sector dynamics.

Abstract

We study Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models; i.e., the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth generation fermion model and the vector-like quark model. Cross sections for these processes can deviate significantly from the standard model predictions due to the one-loop correction to the triple Higgs boson coupling constant. For the one-loop induced processes such as $gg \to hh$ and $γγ\to hh$, where $h$ is the (lightest) Higgs boson and $g$ and $γ$ respectively represent a gluon and a photon, the cross sections can also be affected by new physics particles via additional one-loop diagrams. In the two-Higgs-doublet model and scalar leptoquark models, cross sections of $e^+e^-\to hhZ$ and $γγ\to hh$ can be enhanced due to the non-decoupling effect in the one-loop corrections to the triple Higgs boson coupling constant. In the sequential fourth generation fermion model, the cross section for $gg\to hh$ becomes very large because of the loop effect of the fermions. In the vector-like quark model, effects are small because the theory has decoupling property. Measurements of the Higgs boson pair production processes can be useful to explore new physics through the determination of the Higgs potential.

Figures (27)

• Figure 1: The double Higgs boson production process $gg\to hh$ via gluon fusion at the hadron collider.
• Figure 2: The invariant mass distribution of the cross section of $gg\to hh$ process at the LHC with $\sqrt{s}=14$ TeV for $m_h=120$ GeV (left) and $m_h=160$ GeV (right). The solid, dotted, dashed, long-dashed and dot-dashed curved lines denote the SM prediction, the SM with the positive $100\%$ correction to the $hhh$ coupling constant, that with the $+20\%$ correction, that with the $-20\%$ correction, and that with the $-100\%$ correction, respectively.
• Figure 3: The double Higgs boson production at the $e^+e^-$ collider. The double-Higgs-strahlung process $e^+e^-\to hhZ$ and the vector boson fusion process $e^+e^- \to hh\nu_e \bar{\nu}_e$.
• Figure 4: The cross sections of $e^+e^-\to hhZ$ process at the ILC as a function of collision energy $\sqrt{s}$ for $m_h=120$ GeV (left) and $m_h=160$ GeV (right).
• Figure 5: The double Higgs boson production process $\gamma\gamma\to hh$ at the photon collider.