A common origin for baryons and dark matter
  The origin of the baryon asymmetry of the Universe (BAU) and the nature of
dark matter are two of the most challenging problems in cosmology. We propose a
scenario in which the gravitational collapse of large inhomogeneities at the
quark-hadron epoch generates both the baryon asymmetry and dark matter in the
form of primordial black holes (PBHs). This is due to the sudden drop in
radiation pressure during the transition from a quark-gluon plasma to
non-relativistic hadrons. The collapse to a PBH is induced by fluctuations of a
light spectator scalar field in rare regions and is accompanied by the violent
expulsion of surrounding material, which might be regarded as a sort of
"primordial supernova" . The acceleration of protons to relativistic speeds
provides the ingredients for efficient baryogenesis around the collapsing
regions and its subsequent propagation to the rest of the Universe. This
scenario naturally explains why the observed BAU is of order the PBH collapse
fraction and why the baryons and dark matter have comparable densities. The
predicted PBH mass distribution ranges from sub-solar to several hundred solar
masses. This is compatible with current observational constraints and could
explain the rate, mass and low spin of the black hole mergers detected by
LIGO-Virgo. Future observations will soon be able to test this scenario.
