Gauge dilution in leptogenesis
  We discuss leptogenesis in its natural context, i.e. gauge unification, by including in the analysis the effects of the gauge sector associated to the Majorana neutrinos. It results in stricter bounds on the minimal Majorana mass, depending on the gauge bosons mass, but also prevents to deduce any lower limit on the Yukawa couplings since thermal and re-heating scenarios are now indistinguishable. 
N. Cosme