Asymmetric Dark Matter

A compelling class of theories proposing that dark matter, like ordinary matter, has a fundamental asymmetry between particles and antiparticles. Just as a small excess of matter over antimatter in the early universe led to all the stars and planets we see, a similar imbalance in a hidden "dark sector" could have generated the entire observed abundance of dark matter. This would elegantly explain why there is so much of it, linking its origin to the same type of cosmic process that created us. Instead of being a symmetric, thermal relic, dark matter could be the survivor of an ancient annihilation, a shadow of a primordial asymmetry that shaped both the visible and invisible worlds.

The universe contains roughly five parts dark matter for every part visible matter - similar abundances that may point to a connection between the two. Accordingly, this proposal tries to pass the buck by attributing the matter-antimatter asymmetry to an earlier asymmetry between the producfion of dark matter and dark antimatter, about which nothing is yet known.