Neutrino mass and mixing in the 3-3-1 model and S3 flavor symmetry with   minimal Higgs content
  A new S3 flavor model based on $\mathrm{SU}(3)_C \otimes \mathrm{SU}(3)_L \otimes \mathrm{U}(1)_X$ gauge symmetry responsible for fermion masses and mixings different from our previous work is constructed.   The new feature is a two - dimensional representation of a Higgs anti-sextet under $S_3$ which responsible for neutrino masses and mixings. The neutrinos acquire small masses from only an anti-sextet of $\mathrm{SU(3)}$ which is in a doublet under $S_3$. If the difference of components of the anti-sextet is regarded as a small perturbation, S3 is equivalently broken into identity, the corresponding neutrino mass mixing matrix acquires the most general form and the model can fit the latest data on neutrino oscillation. This way of the symmetry breaking helps us to reduce a content in the Higgs sector, only one an anti-sextet instead of two as in our previous work. Our results show that the neutrino masses are naturally small and a small deviation from the tri-bimaximal neutrino mixing form can be realized. The Higgs potential of the model as well as the minimization conditions and gauge boson masses and mixings is also considered. 
V. V. Vien and H.N.Long
hep-ph