Limit to the Electric Dipole Moment of the Neutron

Abstract

A neutron-beam magnetic resonance experiment with very slow neutrons (as low as 60 m/sec) has been used to set a limit to the neutron electric dipole moment that is more than 100 times lower than the previous limit set by Smith, Purcell, and Ramsey. The value found for the neutron electric dipole moment divided by the proton charge is $\frac{{\ensuremath{\mu}}_{e}}{e}=(\ensuremath{-}2\ifmmode\pm\else\textpm\fi{}3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}22}$ cm. This value is lower than the predictions of many of the time-reversal-noninvariant theories which account for the ${{K}_{2}}^{0}$ decay.