Note on the Decay of theπ-Meson

Assuming the symmetric coupling scheme proposed by Wheeler and Tiomno, and others, we have calculated the ratio of the decay rate $\pi -\mathrm{meson}\to \mathrm{electron}+\mathrm{neutrino}$ to the decay rate of $\pi -\mathrm{meson}\to \mu -\mathrm{meson}+\mathrm{neutrino}$. The electron-neutrino decay proceeds faster, in disagreement with experiment, unless the $\pi$-meson is pseudoscalar and the $\beta$-decay coupling is pseudovector. Hence if the symmetric coupling scheme is corect and no other direct couplings are introduced, the $\pi$-meson must be pseudoscalar and $\beta$-decay must be at least partially pseudovector. If symmetric coupling is not assumed, no conclusion of this kind can be drawn.