A recent study explores a dark matter model based on a "mirror sector" of the Standard Model, interacting with ordinary matter solely through gravity. This mirror sector would possess the same symmetries as the conventional Standard Model, but with significantly higher energy scales and different couplings. The research focuses on how these differences, including distinct Yukawa couplings for the mirror Higgs boson and mirror fermions, would influence the early evolution of the universe.

The authors predict that in this model, a dark phase transition would occur at high temperatures of the baryonic universe, much earlier than the ordinary Standard Model's electroweak phase transition. This transition could be first or second order, depending on the universe's scale and the Yukawa couplings. The case of a second-order phase transition is particularly interesting, as it could leave a detectable imprint on the spectrum of stochastic gravitational waves, a phenomenon potentially observable by future gravitational wave detectors.

The work also examines the ability of this high-scale mirror dark matter to form atoms, showing that in certain scenarios it could have both atomic and subatomic components. An approximation of the total equation of state for this mirror dark matter is provided, and the study discusses how this model could reconcile seemingly contradictory observations from galaxy clusters like the Bullet Cluster and Abell 520, which suggest different dark matter properties at various scales.