Reconstructing the Right-Handed Neutrino Masses in Left-Right Symmetric   Theories
  We introduce a method to extract the right-handed neutrino mass matrix from the Left-Right symmetric seesaw formula and apply it to the study of a simple SUSY SO(10) theory. We find 8 possible solutions for the heavy neutrino spectrum and a richer phenomenology than in the pure type I or type II seesaw mechanism. Leptogenesis is studied in SO(10) and can be accomodated more easily than with the type I dominance. 
Pierre Hosteins