Anomalous spin-1-meson decays from the gauged Wess-Zumino term

We apply a recently proposed chiral-Lagrangian model to discuss the anomalous (unnatural-parity) decays of the low-lying vector and axial-vector mesons. First, about twenty "SU(3) relatives" of the $\omega \to 3\pi$ and $\omega \to {\pi }^0\gamma$ processes previously treated are investigated. The results confirm our confidence in the reliability of the method employed. We then claim that the obscure reaction $D\left(1285\right)\mathrm{}\to \rho \pi \pi$ is an important prototype for studying anomalous processes which do not go through a vector-vector-pseudoscalar vertex. The present model based on a gauging (with phenomenological fields) of the Wess-Zumino term gives a reasonable description of this decay. It also suggests the suppression of processes like axial-vector meson→vector meson plus photon. In the course of this work we take a fresh look at the $A_1-\rho -\pi$ system in the chiral-Lagrangian framework. We note that it is possible to explain together the $A_1$ mass and the widths for $A_1\to \rho \pi$, $\rho \to 2\pi$, and $A_1\to \pi \gamma$.