Progress towards a measurement of the nuclear anapole moment in cesium

We report progress towards a measurement of the anapole moment in cesium, ¹³³Cs. We use an atomic beam interacting with a rf field and Raman field that are coherent with each other. The rf field drives a weak electric dipole interaction between the hyperfine components of the ground state of cesium (6s²S_1/2 F=3 → 6s²S_1/2 F=4), which is weakly allowed due to the influence of the nuclear anapole moment. The Raman field initializes the atoms in a 50-50 mixed state between the two hyperfine ground states. We use detailed numerical calculations of the rf field modes in a cavity and numerical integration of the equations of motion of the state amplitudes to calculate the expected magnitude of the Bloch vector. The relative magnitude of this modulation is expected to be ≈ 5 x 10^-6, which we show to be measurable in the laboratory. We modeled the rf field in the rf cavity we designed to enhance the PNC interaction and reduce the magnetic dipole interaction. Finally, we have observed coherent interaction between the Raman and magnetic rf interactions.