Measurement of Parity Nonconservation and an Anapole Moment in Cesium
The amplitude of the parity-nonconserving transition between the 6S and 7S states of cesium was precisely measured with the use of a spin-polarized atomic beam. This measurement gives Im(E1pnc)/beta = -1.5935(56) millivolts per centimeter and provides an improved test of the standard model at low energy, including a value for the S parameter of -1.3(3)exp (11)theory. The nuclear spin-dependent contribution was 0.077(11) millivolts per centimeter; this contribution is a manifestation of parity violation in atomic nuclei and is a measurement of the long-sought anapole moment.
Wood
CS
The authors are with JILA and the Department of Physics, University of Colorado, Boulder, CO 80309, USA.
Bennett
SC
Cho
D
Masterson
BP
Roberts
JL
Tanner
CE
Wieman
CE