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

Models of asymmetric dark matter (ADM) seek to explain the apparent coincidence between the presentday mass densities of visible and dark matter, Omega(DM) similar or equal to 5v(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 analyze one portal interaction-the neutron portal-in greater detail, in order to satisfy the observational constraints on dark radiation.

Automated summary

This study explores the possibility of a natural mass relationship in symmetric dark matter models, and the use of dark electroweak baryogenesis as a means of generating asymmetry. By investigating the nature of the dark electroweak phase transition and the transfer of particle asymmetries through portal interactions, it is found that both aspects can be successfully implemented in various regions of the parameter space. Further analysis is conducted on the neutron portal interaction to meet observational constraints on dark radiation.