Singlet-Doublet Fermionic Dark Matter and Gravitational Wave in Two Higgs Doublet Extension of the Standard Model

TL;DR

This paper explores a two Higgs doublet model with singlet-doublet fermionic dark matter, analyzing its viability through cosmological, collider, and gravitational wave data, and identifying potential signals for detection.

Contribution

It introduces a novel singlet-doublet fermionic dark matter model within the 2HDM framework, studying its stability, detection prospects, and gravitational wave signatures from phase transitions.

Findings

Viable dark matter parameter space consistent with PLANCK and direct detection limits.

Potential collider signals for the fermionic dark matter.

Gravitational wave signatures from strong first order phase transition.

Abstract

We present a study of singlet-doublet vector-like leptonic dark matter (DM) in the framework of two Higgs doublet model (2HDM), where the dark sector is comprised of one doublet and one singlet vectorlike fermions (VLFs). The DM, that arises as an admixture of the neutral components of the VLFs, is stabilized by an imposed discrete symmetry $\mathcal{Z}_2^{'}$ . We test the viability of the model in the light of observations from PLANCK and recent limits on spin-independent direct detection experiments, and search for its possible collider signals. In addition, we also look for the stochastic gravitational wave (GW) signatures resulting from strong first order phase transition due to the presence of the second Higgs doublet. The model thus offers a viable parameter space for a stable DM candidate that can be probed from direct search, collider and GW experiments.