Mirror matter-type dark matter

TL;DR

Mirror matter presents an exact, unbroken mirror-symmetry framework in which a hidden mirror sector contains identical particle content and interactions. By identifying mirror baryons with the non-baryonic dark matter, the approach naturally links the observed near-equality of ordinary and dark matter densities and yields testable implications for large-scale structure, galactic halos, MACHOs, and direct-detection signals such as the DAMA/NaI modulation. The paper surveys both standard cosmological consequences—like early mirror-photon decoupling and isothermal halo gas—and unconventional predictions, including heating mechanisms for halos, mirror-driven supernova dynamics, and the existence of mirror worlds or mirror-space-bodies in the Solar System. Overall, mirror matter emerges as a well-motivated, falsifiable alternative to WIMPs, with specific, measurable consequences for astrophysics and terrestrial experiments.

Abstract

There are six main things which any non-baryonic dark matter theory should endeavour to explain: (1) The basic dark matter particle properties [mass, stability, darkness]; (2) The similarity in cosmic abundance between ordinary and non-baryonic dark matter, $Ω_B \sim Ω_{dark}$; (3) Large scale structure formation; (4) Microlensing (MACHO) events; (5) Asymptotically flat rotation curves in spiral galaxies; (6) The impressive DAMA/NaI annual modulation signal. Only mirror matter-type dark matter is capable of explaining all six of these desirable features. The purpose of this article is to provide an up-to-date and pedagogical review of this dark matter candidate.