Inclusion of Finite Nuclear Size Effects in the Analysis of Beta-Gamma Directional Correlation Measurements inLa140andGa72

The $\beta -\gamma$ directional correlation in the first forbidden $3^{-}$ → $2^{+}$ $\beta$ transitions of ${\mathrm{La}}^{140}$ and ${\mathrm{Ga}}^{72}$ has been measured as a function of energy. A search for the nuclear matrix element parameters $Y$, $x$, and $u$ which are compatible with the experimental results was conducted. Finite nuclear size effects were included in the analysis by using the electron radial wave functions from the tables of Bhalla and Rose.