Search for Parity Nonconservation in Atomic Bismuth

In a search for optical rotation near the 8755-Å magnetic-dipole absorption line in atomic Bi, our first results set an upper limit $F<\mathrm{}{10}^{-6\mathrm{}}$ on a parity nonconserving amplitude associated with the line. This limit improves upon earlier parity tests in atoms by three orders of magnitude. Further improvement of at least another order of magnitude appears possible by this method which should then provide an exacting test of parity conservation in the neutral weak-current interaction in atoms.