2013

Baryogenesis and Dark Matter with Vector-like Fermions

Fairbairn, Malcolm, Grothaus, Philipp

Understand

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.

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