Progress towards a new parity non-conservation measurement in cesium-133
Atomic parity violation measurements provide a way to probe physics beyond the Standard Model. They can provide constraints on conjectures of a massive Z' boson or a light boson, or searches of dark energy. Using the two-pathway coherent control technique, our group has plans for two new measurements of the weak interaction induced parity non-conservation (PNC) transition moment ԐPNC in cesium. One of them will be on the 6S → 7S transition, while the other is between the hyperfine components of the 6S ground state of cesium.
For an accurate determination of ԐPNC, properties of cesium such as the scalar and vector transition polarizabilities (a, b) are needed, which can be calculated through a sum-over-states method using electric dipole matrix elements. I present improved determinations of several key matrix elements at the 0.2% level, and use the results to calculate new high precision values for a and b. We find a discrepancy between our value of b and the past preferred value, resulting in a significant shift in the value of the weak charge Qweak of the cesium nucleus.