Leptogenesis from a GeV Seesaw without Mass Degeneracy
  For Leptogenesis based on the type-I seesaw mechanism, we present a
systematic calculation of lepton-number violating and purely flavoured
asymmetries within nonequilibrium Quantum Field Theory. We show that sterile
neutrinos with non-degenerate masses in the GeV range can explain the baryon
asymmetry of the Universe via flavoured Leptogenesis. This is possible due to
the interplay of thermal and flavour effects. Our approach clarifies the
relation between Leptogenesis from the oscillations of sterile neutrinos and
the more commonly studied scenarios from decays and inverse decays. We explain
why lower mass bounds for non-degenerate sterile neutrinos derived for
Leptogenesis from out-of-equilibrium decays do not apply to flavoured
Leptogenesis with GeV-scale neutrinos.
