2HDM singlet portal to dark matter

TL;DR

This paper explores a two-Higgs-doublet model with a fermionic dark matter candidate, demonstrating how to reconcile relic abundance with direct detection constraints by disentangling relevant couplings.

Contribution

It introduces a novel approach within a 2HDM framework that separates relic density and direct detection couplings, expanding viable dark matter parameter space.

Findings

Identifies parameter regions consistent with relic abundance and experimental bounds.

Shows that disentangling couplings can evade previous constraints on fermionic Higgs portal models.

Provides a viable model for fermionic dark matter within a 2HDM context.

Abstract

Higgs portal models are the most minimal way to explain the relic abundance of the Universe. They add just a singlet that only couples to the Higgs through a single parameter that controls both the dark matter relic abundance and the direct detection cross-section. Unfortunately this scenario, either with scalar or fermionic dark matter, is almost ruled out by the latter. In this paper we analyze the Higgs-portal idea with fermionic dark matter in the context of a 2HDM. By disentangling the couplings responsible for the correct relic density from those that control the direct detection cross section we are able to open the parameter space and find wide regions consistent with both the observed relic density and all the current bounds.