Baryon Triality and Neutrino Masses from an Anomalous Flavor U(1)
  We construct a concise U(1)_X Froggatt-Nielsen model in which baryon triality, a discrete gauge Z_3 symmetry, arises from U(1)_X breaking. The proton is thus stable, however, R-parity is violated. With the proper choice of U(1)_X charges we can obtain neutrino masses and mixings consistent with an explanation of the atmospheric and solar neutrino anomalies in terms of neutrino oscillations, with no right-handed neutrinos required. The only mass scale apart from M_grav is m_3/2 ~ m_soft. 
Herbi K. Dreiner, Christoph Luhn, Hitoshi Murayama, Marc Thormeier