Measurement of Parity Nonconservation in Atomic Bismuth

Parity-nonconserving optical rotation on the 8757-A magnetic-dipole absorption line in atomic bismuth vapor has been observed and measured. Our result, RequivalentIm(E/sub 1//M/sub 1/) = (-10.4 +- 1.7) x 10/sup -8/, is of the approximate size calculated using the Weinberg-Salam theory of the weak neutral current interaction with sin/sup 2/q/sub W/ = 0.23.