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 will be using an atomic beam interacting with an rf field and Raman field that are coherent with each other. The rf field will drive 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 nuclear anapole moment. The Raman field will initialize 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. We show sinusoidal modulation of the relative population of the two ground states with the phase of the rf field, relative to the phase of the initial superposition state imposed from the Raman interaction. The magnitude of this modulation is ≈ 5 x 10^-6, which we show to be measurable in the laboratory. We have investigated and shown coherent interaction between two Raman interactions.