Z and Z' decays with and without FCNC in 331 models
  In the context of the 331 models, we consider constraints on the extra neutral boson $Z^{\prime}$ predicted by the model, where three different quark family assignments are identified. Using the ansatz of Matsuda as an specific texture for the quark mass matrices, we obtain allowed regions associated with the Z-Z' mixing angle, the mass of the $Z^{\prime}$ boson and the parameter $\beta$ which determines different 331 models. The $Z_{1}$ and $Z_{2}$ decays with and without flavor changing are also considered. The flavor changing decays of the $Z_{1}$ boson into quarks at tree level are highly suppressed by the $Z-Z^{\prime}$ mixing angle, obtaining the same order of magnitude as the standard model prediction at one loop level. The $% Z_{2}$ decay widths are calculated with and without flavor changing, where oblique radiative corrections at one loop accounts for about $1%-4%$ deviations. 
A. Carcamo, R. Martinez and F. Ochoa