K-Leptonic Decay and Partially Conserved Currents

Abstract

An operational definition for the partial conservation of the strangeness-changing vector current is given and applied to leptonic $K^{+}$ and ${K_2}^0$ decay. The $K^{*}$ resonance is explicitly included in the calculation and quantitative agreement with experiment is obtained. A detailed comparison with the $K^{+}$ data of Brown et al. and Dobbs et al. is given. Because of rapid variations of a form factor, it is found that the data of these two groups are not in contradiction. From the ${K_2}^0$ experiment of Luers et al., $I=\frac{1}{2} \mathrm{and} \frac{3}{2}$ currents are seen to exist. $\Lambda \beta$ decay is briefly considered. It is found that an explanation for the slowness of $K$ leptonic decay and the vector part of $\Lambda \beta$ decay may be connected with the partial conservation of the strangeness-changing vector current.