Constraints on bosonic dark matter from observation of old neutron stars

Baryon interactions with bosonic dark matter are constrained by the potential for dark-matter-rich neutron stars to collapse into black holes. We consider the effect of dark matter self-interactions and dark matter annihilation on these bounds, and treat the evolution of the black hole after formation. We show that, for nonannihilating dark matter, these bounds extend up to m(X) similar to 10(5-7) GeV, depending on the strength of self-interactions. However, these bounds are completely unconstraining for annihilating bosonic dark matter with an annihilation cross section of >= 10(-38) cm(3)/s. Dark matter decay does not significantly affect these bounds. We thus show that bosonic dark matter accessible to near-future direct detection experiments must participate in an annihilation or self-interaction process to avoid black hole collapse constraints from very old neutron stars. DOI: 10.1103/PhysRevD.87.055012