Lepton masses and mixing in $SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}$   models with a $S_3$ flavor symmetry
  We propose a model based on the gauge group $SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}$ with an extra $S_{3}$ flavor symmetry, which accounts for the lepton masses and mixing. The small active neutrino masses are generated via a double seesaw mechanism. In this scenario, the spectrum of neutrinos presents very light, light and very heavy masses. The model predicts a quasidegenerate normal hierarchy active neutrino mass spectrum and the relation $\Delta m_{21}^{2}\ll \Delta m_{31}^{2}$ arises from effective six-dimensional operators. The obtained neutrino mixing parameters are in agreement with the neutrino oscillation experimental data. We find CP violation in neutrino oscillations with a Jarlskog invariant of about $10^{-2}$. 
A. E. C\'arcamo Hern\'andez, E. Cata\~no Mur, R. Martinez
hep-ph