Calculable lepton masses, seesaw relations and four neutrino mixings in   a 3-3-1 model with extra U(1) symmetry
  We propose a scheme in that the masses of the heavier leptons obey seesaw type relations. The light lepton masses, except the electron and the electron neutrino ones are generated by one loop level radiative corrections. We work in a version of the 3-3-1 electroweak model that predicts singlets (charged and neutral) of heavy leptons beyond the known ones. An extra U(1)_Omega symmetry is introduced in order to avoid the light leptons get masses at the tree level. The electron mass induces an explicit symmetry breaking at U(1). We discuss also the mixing matrix among four neutrinos. The new energy scale required is not higher than a few TeV. 
Nelson V. Cortez, Mauro D. Tonasse (Sao Paulo State Univ., Registro)