Revisiting the Inert Scalar Dark Matter with Vector-like Quarks

TL;DR

This paper extends the inert doublet model by adding vector-like quarks, which helps achieve the correct dark matter relic abundance and relaxes detection constraints, opening new detection possibilities.

Contribution

Introducing a vector-like quark into the inert doublet model to address relic abundance and detection constraints, enhancing dark matter phenomenology.

Findings

VLQ increases relic abundance for DM masses above 550 GeV

VLQ enables smaller Higgs-inert scalar couplings, easing direct detection constraints

Extended model offers promising detection prospects in collider experiments

Abstract

The inert doublet model (IDM), a minimal extension of the Standard Model (SM), provides a scalar dark matter (DM) candidate that belongs to the additional Higgs doublet. The model faces challenges in achieving the correct relic abundance for compressed spectra and DM masses in the high-mass range. In this work we introduce a $Z_2$-odd singlet vector-like quark (VLQ) into the IDM framework that helps us alleviate these issues and provide new channels of contributions to the relic abundance. The VLQ not only enhances the DM relic abundance for masses above $~550$ GeV but also eases constraints from direct detection experiments by enabling smaller couplings between the inert scalars and the SM Higgs. We analyze the impact of the VLQ on DM phenomenology, including relic density, direct and indirect detection constraints. The results demonstrate that the extended IDM framework not only resolves existing limitations in the compressed spectrum but also offers exciting prospects for detection in current and future collider experiments.