Oakes Theory of Weak Interactions and Parity-Nonconserving Nuclear Forces

The parity-nonconserving nucleon-nucleon potential is calculated from the Oakes theory of weak interactions on the assumption that $\ensuremath{\pi}$ and $\ensuremath{\rho}$ exchange terms dominate. It is found that this theory predicts a circular polarization of \ifmmode\pm\else\textpm\fi{}(1.8\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ for 482-keV $\ensuremath{\gamma}$ ray from $^{181}\mathrm{Ta}$. The observed polarization is -(0.06\ifmmode\pm\else\textpm\fi{}0.01)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$.