PBH Evaporation, Baryon Asymmetry, and Dark Matter

Sufficiently light primordial black holes (PBH) could evaporate in the very early universe and dilute the preexisting baryon asymmetry and/or the frozen density of stable relics. The effect is especially strong in the case that PBHs decayed if and when they dominated the cosmological energy density. The size of the reduction is first calculated analytically under the simplifying assumption of the delta-function mass spectrum of PBH and instant decay approximation. In the realistic case of exponential decay and for an extended mass spectrum of PBH the calculations are made numerically. Resulting reduction of the frozen number density of the supersymmetric relics opens for them a wider mass window to become viable dark matter candidate.