Further Analysis of the Decayπ→e+ν+γ

We have recalculated the structure-dependent part of the decay $\pi \to e+\nu +\gamma$, using the conserved vector current hypothesis, in order to derive information on the axial-vector-current form factor. Earlier calculations of Bludman and Young have been extended by including, as a phenomenological parameter, the axial-vector contribution relative to polar-vector, and by calculating integrals of the decay rate over various portions of phase space likely to be measured. The experiments can be analyzed in terms of the $\pi \rho$ coupling to the axial-vector current. We conclude that the recent experiments of Depommier et al. establish the presence of such axial-vector structure contributing to the decay, but that one cannot assign this component to a weak-interacting vector meson rather than to strong-interaction structure.