On Nature of Right-Handed Singlet in 331 Model and Anomalies before and   after SSB
  The gauge invariant and anomaly-free 331 model is studied with $R_\xi$ gauges in order to see which of the right-handed singlet between the case (i), assigning the bosonic singlet to the counterpart of 3 and $\bar 3$ representations, and the case (ii), assigning fermionic siglet to the counterpart of the left-handed 3 representation and assigning the antifermionic singlet to that of the left-handed $\bar 3$ representaion, should be assigned in physics but not mathematics to the counterparts of the left-handed fundamental 3 representation and the left-handed complex conjugate $\bar 3$ representation. It is shown that through an effect on the Yukawa interaction of the transformation property of the singlet it depends on the choices of the case (i) or the case (ii) whether the anomaly coefficients even after the spontaneous symmetry breaking (SSB) vanish or not, and the coefficients vanish only in the case (ii) but do not in the case (i). Furthermore, it is pointed out that the BRS invariance after the SSB holds for the case (ii) and (i-b) of two possibilities in the choice for the mass eigenstates in the case (i) and thus the BRS invariance does not necessarily ensure renormalizability of the theory though the inverse of it holds. 
T. Kiyan, T. Maekawa, M. Masuda and H. Taira