Review of asymmetric dark matter

TL;DR

This review analyzes asymmetric dark matter (ADM) as a class of models where the present DM abundance originates from a particle–antiparticle asymmetry linked to the visible baryon asymmetry. It develops a formal symmetry framework for ADM, surveys multiple asymmetry-generation mechanisms (including out-of-equilibrium decays, Affleck-Dine dynamics, and phase-transition scenarios), and discusses a variety of concrete ADM models such as mirror DM, darkogenesis, and pangenesis. The authors synthesize ADM phenomenology across cosmology, structure formation, direct and indirect detection, stellar capture, and collider signatures, highlighting how ADM can mimic cold DM on large scales while offering distinctive small-scale, radiation, and mediator-related signals. They emphasize the role of dark forces, dark radiation, and potential multi-component dark sectors, and they assess current constraints from BBN, CMB, astrophysical observations, and accelerator experiments. The work concludes that ADM remains a compelling alternative to the WIMP paradigm, with rich theoretical structures and several experimentally accessible avenues for probing dark-sector dynamics.

Abstract

Asymmetric dark matter models are based on the hypothesis that the present-day abundance of dark matter has the same origin as the abundance of ordinary or visible matter: an asymmetry in the number densities of particles and antiparticles. They are largely motivated by the observed similarity in the mass densities of dark and visible matter, with the former observed to be about five times the latter. This review discusses the construction of asymmetric dark matter models, summarizes cosmological and astrophysical implications and bounds, and touches on direct detection prospects and collider signatures.