Two-Pole Model for the ${\eta }_{3\pi }$ Decays

$\eta \to 3\pi$ decays are described by a model in which the amplitudes are assumed to be dominated by two meson poles. The model is characterized by scalar, vector, and axial-vector meson poles. The strong-coupling constants in the model are obtained from the experimental decay widths. Adopting the tadpole model, the effective electromagnetic coupling is given in terms of the electromagnetic mass difference of kanos. If the $D-E$ mixing and $\eta -{\eta }^{\prime }$ mixing are included, then the branching ratio, the slope, and the decay rate for the $\eta \to 3{\pi }^0$ are found to be in good agreement with experiment.