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 $R<1.7\mathrm{}\times {10}^{-2\mathrm{}}{\mathrm{pc}}^{-3\mathrm{}}{\mathrm{yr}}^{-1\mathrm{}}$, (ii) the fraction of the Universe's mass going into PBHs with particular mass, and (iii) the average density of PBHs in the Universe.