The economical 3-3-1 model revisited

We show that the economical 3-3-1 model poses a very high new physics scale of the order of 1000~TeV due to the constraint on the flavor-changing neutral current. The implications of the model for neutrino masses, inflation, leptogenesis, and superheavy dark matter are newly recognized. Alternatively, we modify the model by rearranging the third quark generation differently from the first two quark generations, as well as changing the scalar sector. The resultant model now predicts a consistent new physics at TeV scale unlike the previous case and may be fully probed at the current colliders. Particularly, due to the minimal particle contents, the models under consideration manifestly accommodate dark matter candidates and neutrino masses, with novel and distinct production mechanisms. The large flavor-changing neutral currents that come from the ordinary and exotic quark mixings can be avoided due to the approximate $B-L$ symmetry.Comment: 21 pages; english writing improved, dark matter stability stated, and references added; matches journal versio

The 3-3-1 model with A_4 flavor symmetry

We argue that the A_4 symmetry as required by three flavors of fermions may well-embed in the SU(3)_C X SU(3)_L X U(1)_X gauge model. The new neutral fermion singlets as introduced in a canonical seesaw mechanism can be combined with the standard model lepton doublets to perform SU(3)_L triplets. Various leptoscalar multiplets such as singlets, doublets, and triplets as played in the models of A_4 are unified in single SU(3)_L antisextets. As a result, naturally light neutrinos with various kinds of mass hierarchies are obtained as a combination of type I and type II seesaw contributions. The observed neutrino mixing pattern in terms of the Harrison-Perkins-Scott proposal is obtained by enforcing of the A_4 group. The quark masses and Cabibbo-Kobayashi-Maskawa mixing matrix are also discussed. By virtue of very heavy antisextets the nature of the vacuum alignments of scalar fields can be given.Comment: Version published by PR