Hyperfine Structure Separation of the Ground State of 87Rb Measured with an Optically Pumped Atomic Beam

Abstract
Using an optically pumped atomic beam resonator a redetermination of the hyperfine structure separation of the ground state of 87Rb has been made. The zero-field value Δ𝒱0 = 6 834 682 612.8 ± 0.5 Hz agrees with previous determinations made with conventional atomic beams.