Measurement of the neutron magnetic moment

The neutron magnetic moment ${\mu }_n$ has been measured with an improvement of 2 orders of magnitude in experimental accuracy. The separated-oscillatory-field magnetic resonance technique was employed using slow neutrons and protons (in flowing water) in the same magnetic field. We find the ratio of neutron to proton moment to be $\frac{{\mu }_n}{{\mu }_p}=-0.684\mathrm{}97935\left(17\right)\mathrm{}$ (0.25 ppm). Expressed in Bohr magnetons ${\mu }_B$ this gives $\frac{{\mu }_n}{{\mu }_B}=-1.041\mathrm{}87564\left(26\right)\mathrm{}\times {10}^{-3\mathrm{}}$. Expressed in nuclear magnetons ${\mu }_N$, $\frac{{\mu }_n}{{\mu }_N}=-1.913\mathrm{}04184\left(88\right)\mathrm{}$.