Upper Limit on Parity-Nonconserving Optical Rotation in Atomic Bismuth

Abstract

We have searched for optical rotation near the 8757-\AA{} magnetic-dipole absorption line in atomic bismuth vapor. The experiment is sensitive to parity nonconservation in the weak neutral-current interaction between electrons and nucleons in atoms. We find $R\ensuremath{\equiv}\mathrm{Im}(\frac{{E}_{1}}{{M}_{1}})=(\ensuremath{-}0.7\ifmmode\pm\else\textpm\fi{}3.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$, which is considerably smaller than the value $R=\ensuremath{-}2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ obtained by central-field calculations for this bismuth line using the Weinberg-Salam theory of neutral currents.