Upper Limit on Parity-Nonconserving Optical Rotation in Atomic Bismuth

Abstract

We have searched for optical rotation near the 8757-Å 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 $R\equiv \mathrm{Im}\left(\frac{E_1}{M_1}\right)=(-0.7\mathrm{}\pm 3.2)\times {10}^{-8\mathrm{}}$, which is considerably smaller than the value $R=-2.5\mathrm{}\times {10}^{-7\mathrm{}}$ obtained by central-field calculations for this bismuth line using the Weinberg-Salam theory of neutral currents.