Baryogenesis Through Mixing of Heavy Majorana Neutrinos
  A mechanism is presented, in which the mixing of right handed heavy Majorana neutrinos creates a $CP-$asymmetric universe. When these Majorana neutrinos subsequently decay more leptons than anti-leptons are produced. The lepton asymmetry created by this new mechanism can exceed by a few orders of magnitude any lepton asymmetry originating from direct decays. The asymmetry is finally converted into a baryon asymmetry during the electroweak phase transition. 
Marion Flanz, Emmanuel A. Paschos, Utpal Sarkar and Jan Weiss