Higgs boson pair production through gauge boson fusion at linear colliders within the general 2HDM

TL;DR

This paper investigates Higgs boson pair production via gauge boson fusion at linear colliders within the general 2HDM, highlighting its sensitivity to Higgs self-interactions and potential for probing the Higgs potential.

Contribution

It provides a detailed analysis of Higgs pair production in the 2HDM at linear colliders, emphasizing the process's sensitivity to Higgs self-couplings and its dominance over other mechanisms.

Findings

Cross-sections up to 1 pb at 1 TeV in favorable scenarios.

Potential for 10^5 events per 100 fb^{-1} luminosity.

Higgs pair events could be the main signature in TeV-class colliders.

Abstract

Inclusive Higgs boson pair production through the mechanism of gauge boson fusion e^{+} e^{-} -> V* V* -> h h + X (V=W,Z) in the general Two-Higgs-Doublet Model (2HDM), with h=h^0,H^0,A^0,H^{\pm}, is analyzed at order \alpha^4_{ew} in the linear colliders ILC and CLIC. This kind of processes is highly sensitive to the trilinear Higgs (3H) boson self-interactions and hence can be a true keystone in the reconstruction of the Higgs potential. For example, in the ILC at 1 TeV, the most favorable scenarios yield cross-sections up to roughly 1 pb, thus entailing 10^5 events per 100 fb^{-1} of integrated luminosity, whilst remaining fully consistent with the perturbativity and unitarity bounds on the 3H couplings, the electroweak precision data and the constraints from BR(b->s\gamma). Comparing with other competing mechanisms, we conclude that the Higgs boson-pair events could be the dominant signature for Higgs-boson production in the TeV-class linear colliders for a wide region of the 2HDM parameter space, with no counterpart in the Minimal Supersymmetric Standard Model. Owing to the extremely clean environment of these colliders, inclusive 2H events should allow a comfortable tagging and might therefore open privileged new vistas into the structure of the Higgs potential.