Collapse of Captured Non-Annihilating Bosonic Dark Matter in Neutron Stars

Determine whether the captured non-annihilating bosonic dark matter in neutron stars collapses to form a black hole, taking into account that the outcome is controlled by the dark-matter self-interactions of order m_{\chi_1}^2/f_D^2.

Background

The model contains a stable real scalar dark-matter state $\chi_1$ that does not appreciably annihilate. In neutron stars, the high infall velocity can make the inelastic transition $\chi_1 N\to\chi_2 N$ kinematically accessible, allowing dark matter to be captured and subsequently deposit energy through the decay $\chi_2\to\chi_1\pi^0\gamma$.

Because the captured population is non-annihilating, it can accumulate inside the neutron star. The paper notes that whether this accumulated bosonic population undergoes gravitational collapse into a black hole depends on its self-interactions, estimated in this model to be of order $m_{\chi_1}^2/f_D^2$, but does not resolve the collapse question.