Measurement of parity non-conserving transitions in cesium via two-pathway coherent control

With the development and application of the coherent control technique, higher precision measurements of weak transition amplitudes have become possible, which may enhance our knowledge of physics even further. In our weak interaction measurement efforts, we seek to measure the weak charge of cesium with far less uncertainty than previously reported by others.

The weak charge can be derived from the transition amplitudes of the highly forbidden transition, 6S -> 7S, where the transition becomes weakly allowed due to the weak interaction between the nucleons and the valence electron. The transition amplitude is many orders magnitude smaller than a regular electric-dipole-allowed transition, which makes it extremely susceptible to noise and other systematic errors. Although the most recent measurement results of the transition have appreciably low uncertainty, a better measurement will not only shed light on the nature of the weak force but also provide a unique probe for the search of dark matter.