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Mirror matter and other dark matter models

This brief review discusses the role of the mirror matter (MM) model in the context of the dark matter (DM) problem. First proposed in 1966 by Kobzarev, Okun, and Pomeranchuk, MM is the oldest but still viable candidate—admittedly with some modifications—for describing real DM. The difficulties of the standard model with WIMPs (weakly interacting massive particles) are outlined, and situations where mirror matter could be helpful in resolving some of them are identified. Mirror particles are a subclass of a wider set of ADM (asymmetric DM, where DM particles do not annihilate, unlike supersymmetric particles in ). References on limits for cross sections of ADM model bosons accreting onto neutron stars are provided. They can be much lower than the experimental limits for WIMPs.