Interplay between Higgs inflation and dark matter models with dark $U(1)$ gauge symmetry

TL;DR

This paper explores a dark $U(1)_D$ extension of the Standard Model, analyzing dark matter candidates and multiple Higgs inflation scenarios, and identifies parameter spaces consistent with observational constraints.

Contribution

It introduces a model with two dark matter candidates and multiple Higgs inflation pathways, providing a comprehensive numerical analysis of their interplay.

Findings

Dark fermion can dominate over dark vector boson in certain parameter regions.

Higgs inflation constrains dark matter parameter space significantly.

Dark Higgs field is crucial for both dark matter phenomenology and inflation.

Abstract

We investigate dark matter phenomenology and Higgs inflation in a dark $U(1)_D$-extended model. The model features two dark matter candidates, a dark fermion and a dark vector boson. When the fermion dark matter $\psi$ is heavier than the vector dark matter $W_D$, there is an ample parameter space where $\psi$ is dominant over $W_D$. The model can then easily evade the stringent bounds from direct detection experiments, since $\psi$ has no direct coupling to the Standard Model particles. Furthermore, the model can accommodate inflation in three different ways, one along the Standard Model Higgs direction, one along the dark Higgs direction, and one along the combination of the two. Considering the running of the parameters and various observational constraints, we perform a detailed numerical analysis and identify allowed parameter spaces that explain both dark matter and Higgs inflation in a unified manner. We discuss in detail how the imposition of Higgs inflation severely constrains the dark matter parameter space. The existence of the dark Higgs field is found to play a crucial role both in dark matter phenomenology and in generalised Higgs inflation.