Primordial Black Holes as All Dark Matter

Abstract

We argue that a primordial black hole is a natural and unique candidate for all dark matter. We show that, in a smooth-hybrid new double inflation model, a right amount of the primordial black holes, with a sharply-defined mass, can be produced at the end of the smooth-hybrid regime, through preheating. We first consider masses < 10^(-7)M_sun which are allowed by all the previous constraints. We next discuss much heavier mass 10^5 M_sun hinted at by entropy, and galactic size evolution, arguments. Effects on the running of the scalar spectral index are computed.