Double inflation as a single origin of primordial black holes for all dark matter and LIGO observations

A primordial black hole (PBH) is one of the leading nonparticle candidates for dark matter (DM). Although several observations severely constrain the amount of PBHs, it was recently pointed out that there is an uncertainty on the microlensing constraints below 10^-10 M_, which was ignored originally but may weaken the constraints significantly. In this paper, facing this uncertainty, we investigate the possibility that PBHs can make up all DM in a broad mass spectrum. Moreover, we propose a concrete inflation model that can simultaneously produce PBHs for all DM in a broad mass spectrum around O (10^-13) M_ and PBHs for LIGO events in a sharp mass spectrum at O (10) M_.