Weak Scale Leptogenesis, R-symmetry, and a Displaced Higgs
  We present a supersymmetric model of leptogenesis in which the right-handed neutrinos have weak scale masses and O(10-2-10-3) yukawa couplings. The model employs an R-symmetry at the weak scale that forces neutrino masses to be proportional to the gravitino mass. We predict that the lightest right-handed neutrino decays to a displaced Higgs and neutrino and that the NLSP is long-lived on collider scales. These could be striking signatures at the LHC if, for instance, the right-handed neutrino is produced in a cascade decay. 
Keith Rehermann and Christopher M. Wells
hep-ph