Precise measurement of parity nonconserving optical rotation at 876 nm in atomic bismuth.
We report the first precise measurements of parity nonconserving (PNC) optical rotation in atoms, carried out on the 876-nm M 1 transition in bismuth. We obtain R i =Im(E 1 i PNC /M 1)=(-10.12±0.20)×10 -8 , where E1 i PNC is the E1 amplitude mixed into the transition by the nuclear spin-independent PNC interaction. The result is in excellent agreement with the standard model of the electroweak interaction