Primordial Black Holes in Higgs-$R^2$ Inflation as a Whole Dark Matter
  Primordial black holes are produced in a minimal UV extension to the Higgs
inflation with an included $R^2$ term. We show that for parameters consistent
with Standard Model measurements and Planck observation results lead to $M_{\rm
PBH} \in (10^{-16}, 10^{-15}) M_\odot$ primordial black holes with significant
abundance, which may consist the majority of dark matter.
