Nuclear Magnetic Moment of ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$: Resolving a Discrepancy

The ratio of the nuclear $g_I$ factor to the atomic $g_J$ factor in ${}_{}{}^{85}{}_{}{}^{}\mathrm{Rb}$ has been measured by the atomic-beam magnetic-resonance technique to be $\frac{g_I\left(\mathrm{uncorr}\right)}{g_J}=-1.466478\mathrm{}\left(22\right)\mathrm{}\times {10}^{-4\mathrm{}}$. This result is in excellent agreement with recent optical-pumping measurements but is lower than a previously reported atomic-beam result.