Baryogenesis and Dark Matter with Vector-like Fermions
  We show that vector-like fermions can act as the dark matter candidate in the
universe whilst also playing a crucial role in electroweak baryogenesis through
contributing to the barrier in the one-loop thermal scalar potential. In order
for the new fermions to give rise to a strong first order phase transition, we
show that one requires rather large Yukawa couplings in the new sector, which
are strongly constrained by electroweak precision tests and perturbativity.
Strong couplings between the dark matter candidate and the Higgs boson
intuitively lead to small values of the relic density and problems with dark
matter direct detection bounds. Nevertheless, when considering the most general
realisation of the model, we find regions in the parameter space that respect
all current constraints and may explain both mysteries simultaneously.
