Non-Abelian anomaly and vector-meson decays

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Abstract
We propose an extension of the old, fairly successful, phenomenological prescription for adding spin-1 fields to the chiral Lagrangian of pseudoscalar mesons to the case where the Wess-Zumino term is present. This leads to the possibility of describing within the effective-Lagrangian framework a whole class of "unnatural-parity" hadronic reactions. In particular, we study the wellknown (pure hadronic) ω→3π and (radiative) ω→π0γ processes, and find good agreement with experiment, comparable to that for any of the current-algebra "theorems." The construction of the Lagrangian is seen to involve subtle theoretical issues. We are led to examine in more detail Witten's "trial-and-error" gauging of the Wess-Zumino term and note that the Bardeen form of the anomaly seems more suitable than the left-right-symmetric form for constructing an effective model with phenomenological spin-1 fields.