Implementing asymmetric dark matter and dark electroweak baryogenesis in a mirror two-Higgs-doublet model

Alexander C Ritter,Raymond R Volkas

doi:10.1103/physrevd.104.035032

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.

Highlights

Determining the particle nature of dark matter (DM) remains one of the most important problems in fundamental physics
The purpose of the present paper is (i) To construct an alternative version of the theory where asymmetry generation occurs through dark electroweak baryogenesis, which is another reasonable mechanism that is worth exploring
We show that there is sufficient freedom to arrange for the dark electroweak phase transition to be strongly first order, as required for this mechanism

Summary

Introduction

Determining the particle nature of dark matter (DM) remains one of the most important problems in fundamental physics. While there are some important constraints on its nature—for example, it cannot be hot DM because large-scale structure formation yields incorrect results—DM is famous, or notorious, for being anything from “fuzzy” scalars at the 10−22 eV mass scale [1], to several solar-mass primordial black holes [2], with many different kinds of possibilities at intermediate mass scales [3]. It makes sense to carefully examine what we do know observationally about DM, because there may be clues already lurking in the data about what its fundamental nature is. One fact that may be important is the apparent coincidence in the present-day cosmological mass densities of visible and dark matter, which obey. ΩDM ≃ 5 ΩVM; ð1Þ where ΩX is the mass density of X divided by the critical density [4].

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Results

Conclusion