It is shown that the conserved current theory of Feynman and Gell-Mann is consistent with knowledge of RaE beta decay. This assertion is made by extending the Siegert theorem to beta decay and comparing the theoretical prediction for $〈\alpha 〉$ with the experimental data, which are obtained from recent electron polarization and spectrum measurements. The Coulomb terms are evaluated using the Ahrens-Feenberg approximation. The conserved and nonconserved (conventional) theories are differentiated by the presence or absence of the exchange contributions. These are also evaluated by the Ahrens-Feenberg approximation. This re-analysis leads to an even larger disagreement between the shell-model prediction and the phenomenological nuclear matrix elements, $\frac{〈|\sigma \times \hat{r}|〉}{i〈\hat{r}〉}$. The origin of the disagreement is discussed. Several possible effects of the meson-cloud beta decay in a nucleus are also surveyed in the course of study.

• Received 4 August 1961

DOI:https://doi.org/10.1103/PhysRev.126.202