Local flux of low-energy antiprotons from evaporating primordial black holes.

We investigate low-energy cosmic-ray antiprotons ( $\overline{p}$'s) arising from the fragmentation of quarks and gluons emitted from evaporating primordial black holes (PBHs). To calculate the local interstellar flux of these $\overline{p}$'s, their propagation in the Galaxy is described by a 3D Monte Carlo simulation based on the diffusion model. This flux is used with recent observations to derive new upper limits on (i) the local PBH explosion rate $Rl1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}{\mathrm{pc}}^{\ensuremath{-}3}{\mathrm{yr}}^{\ensuremath{-}1}$, (ii) the fraction of the Universe's mass going into PBHs with particular mass, and (iii) the average density of PBHs in the Universe.