$\mathrm{ft}$ Values of Some $0^{+}$ → $0^{+}$ Beta Decays and the Value of the Vector Coupling Constant

We calculate the correct changes in the $f_{0}t$ values for some $0^{+}$ → $0^{+}$ nuclear B decays due to the radiative corrections, and compare the different results obtained by using the radiative corrections as given by Kinoshita and Sirlin, by Källén, and by the present authors. Our calculation of the radiative correction differs from the others in making use of a configuration space cutoff, which is what appears in the Fermi function. We have also treated the screening effects, due to the orbital electrons on the Fermi function, analytically in perturbation theory to order $Z\alpha$, and agree precisely with Rose's results. The corrected values for $G_{\beta }$ and $\frac{(G_{\mu }-G_{\beta })}{G_{\mu }}$ are given, as well as a table explicitly delineating the percentage corrections to the $f_{0}t$ values due to screening, radiative corrections, and finite nuclear size.