Abstract
If dark matter couples to force mediators that are much lighter than
itself, then its interactions manifest as long-ranged. This gives rise to
non-perturbative effects, including the existence of bound states. The
formation of stable or metastable dark matter bound states can affect the
dark matter phenomenology very significantly, including the dark matter
relic density, indirect and direct detection signals, as well as the
dark-matter self-scattering inside galaxies.