Chiral perturbation theory for anomalous processes

Abstract

A general expression containing all the divergences in Chiral Perturbation Theory at one loop for anomalous processes has been calculated. The nonrenormalization of some amplitudes (Adler-Bardeen theorem) is observed. The different types of corrections are identified. The contributions from vector meson exchange are determined for all anomalous processes. Explicit cancellation of divergences is shown for π0, η and η′ decays to γγ*. The dependence on the γ* mass squared is predicted to be essentially the same for all the three processes. It proceeds mainly through the VMD estimate of the finite parts of the next order Lagrangian and compares reasonably well with the available experimental data.