Parity-Nonconserving Optical Rotation in Atomic Lead

Abstract

The search for parity nonconservation in heavy elements has been extended to the 1.28-μm ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}\to {}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$ magnetic dipole transition in atomic lead. The experimental result, $R=\mathrm{Im}\left(\frac{E1\mathrm{}}{M1\mathrm{}}\right)=(-9.9\mathrm{}\pm 2.5)\times {10}^{-8\mathrm{}}$, agrees, within the present uncertainties in experiment and atomic theory, with the prediction, $R=-13\mathrm{}\times {10}^{-8\mathrm{}}$, derived from the Weinberg-Salam-Glashow theory of weak neutral-current interactions.