Realistic neutron star constraints on bosonic asymmetric dark matter

Abstract

It has been argued that the existence of old neutron stars excludes the possibility of nonannihilating light bosonic dark matter, such as that arising in asymmetric dark matter scenarios. If nonannihilating dark matter is captured by neutron stars, the density will eventually become sufficient for black hole formation. However, the dynamics of collapse is highly sensitive to dark matter self-interactions. Repulsive self-interactions, even if extremely weak, can prevent black hole formation. We argue that self-interactions will necessarily be present and estimate their strength in representative models. We also consider the coannihilation of dark matter with nucleons, which arises naturally i..