Sizable triple Higgs couplings in the 2HDM: Prospects for future $e^+e^-$ colliders

TL;DR

This paper investigates large triple Higgs couplings within the 2HDM framework, analyzing their effects on future $e^+e^-$ collider production cross sections while satisfying experimental and theoretical constraints.

Contribution

It identifies benchmark scenarios with sizable triple Higgs couplings in the 2HDM and evaluates their impact on specific Higgs pair production processes at future colliders.

Findings

Large triple Higgs couplings significantly enhance production cross sections.

Benchmark planes with large couplings are consistent with current constraints.

Triple Higgs couplings influence key collider observables.

Abstract

In the framework of the $\mathcal{CP}$ conserving Two Higgs Doublet Model (2HDM), type I and II, we study the triple Higgs couplings with at least one light $h$ Higgs boson that is identified by the 125 GeV Higgs boson. We define benchmark planes that exhibit large values of triple Higgs couplings, while being in agreement with all experimental and theoretical constraints. Finally, we analyze the impact of the triple Higgs couplings on the production cross section of two neutral Higgs bosons in two channels, $\sigma(e^+e^-\to h_i h_j Z)$ and $\sigma(e^+e^- \to h_i h_j \nu\bar{\nu})$ with $h_i h_j = hh, hH, HH, AA$. We show that the triple Higgs couplings have an important impact on these $e^+e^-$ production cross sections.