Implementing Asymmetric Dark Matter and Dark Electroweak Baryogenesis in a Mirror Two-Higgs-Doublet Model

TL;DR

This paper explores a mirror two-Higgs-doublet model to explain the dark matter abundance and baryogenesis, demonstrating successful asymmetry generation through dark electroweak phase transition and portal interactions, consistent with observational constraints.

Contribution

It introduces a novel implementation of dark electroweak baryogenesis in a mirror two-Higgs-doublet model, linking dark matter mass and asymmetry generation mechanisms.

Findings

Successful dark electroweak phase transition in the model.

Effective transfer of asymmetries via portal interactions.

Compatibility with dark radiation observational constraints.

Abstract

Models of asymmetric dark matter (ADM) seek to explain the apparent coincidence between the present-day mass densities of visible and dark matter, $\Omega_{\mathrm{DM}} \simeq 5\Omega_{\mathrm{VM}}$. However, most ADM models only relate the number densities of visible and dark matter without motivating the similar particle masses. We expand upon a recent work that obtained a natural mass relationship in a mirror matter ADM model with two Higgs doublets in each sector, by looking to implement dark electroweak baryogenesis as the means of asymmetry generation. We explore two aspects of the mechanism: the nature of the dark electroweak phase transition, and the transfer of particle asymmetries between the sectors by the use of portal interactions. We find that both aspects can be implemented successfully for various regions of the parameter space. We also analyse one portal interaction -- the neutron portal -- in greater detail, in order to satisfy the observational constraints on dark radiation.