We reconsider the possibility that the observed baryon asymmetry was
generated by the evaporation of primordial black holes that dominated the early
universe. We present a simple derivation showing that the baryon asymmetry is
insensitive to the initial black hole density and the cosmological model but is
sensitive to the temperature-dependence of the CP and baryon-violating (or
lepton-violating) interactions. We also consider the possibility that black
holes stop evaporating and form Planck-mass remnants that act as dark matter.
We show that primordial black holes cannot simultaneously account for both the
observed baryon asymmetry and the (remnant) dark matter density unless the
magnitude of CP violation is much greater than expected from most particle
physics models. Finally, we apply these results to ekpyrotic/cyclic models, in
which primordial black holes may form when branes collide. We find that
obtaining the observed baryon asymmetry is compatible with the other known
constraints on parameters.
Comment: 19 pages, 5 figures
Subjects: High Energy Physics - Theory; Astrophysics