Constraints on primordial black holes as dark matter candidates from capture by neutron stars

We put constraints on primordial black holes (PBHs) as dark matter candidates by considering their capture by neutron stars (NSs). If a PBH is captured by a NS, the latter is accreted onto the PBH in a very short time leading to the star's destruction. Mere observations of NSs put limits on the abundances of PBHs. We are able to exclude PBHs as dark matter from observations of NSs in globular clusters for PBHs masses $10^{18} \text{g} \lesssim m_\text{BH}\lesssim 5\times10^{23} \text{g}$.