The Evidence of the Once-Forbidden Spectra for the Law ofβ-Decay

A series of empirical arguments has developed which leave two alternatives for the law of $\beta$-interaction: an $\mathrm{STP}$ (scalar+tensor pseudoscalar) or a $\mathrm{VTP}$ ($V\equiv \mathrm{vector}$) combination. We offer a new argument, based on an interpretation of the reported "allowed" shapes of once-forbidden spectra, which favors the $\mathrm{STP}$ over the $\mathrm{VTP}$ form. This new development may be important because it is a possible last step in arriving at a unique law of $\beta$-decay (i.e., all three components of the $\mathrm{STP}$ form would become both admissible and necessary).