GUT Baryogenesis With Primordial Black Holes
  In models of baryogenesis based on Grand Unified Theories (GUTs), the baryon
asymmetry of the universe is generated through the CP and baryon number
violating, out-of-equilibrium decays of very massive gauge or Higgs bosons in
the very early universe. Recent constraints on the scale of inflation and the
subsequent temperature of reheating, however, have put pressure on many such
models. In this paper, we consider the role that primordial black holes may
have played in the process of GUT baryogenesis. Through Hawking evaporation,
black holes can efficiently generate GUT Higgs or gauge bosons, regardless of
the masses of these particles or the temperature of the early universe.
Furthermore, in significant regions of parameter space, the black holes
evaporate after the electroweak phase transition, naturally evading the problem
of sphaleron washout that is normally encountered in GUT models based on
$SU(5)$. We identify a wide range of scenarios in which black holes could
facilitate the generation of the baryon asymmetry through the production and
decays of GUT bosons.
