Upper Limit of the Electric Dipole Moment of the Electron

Abstract

A new upper limit on the electric dipole moment of the electron is established by measurements of the scattering of electrons by ${\mathrm{He}}^{4}$ at 180\ifmmode^\circ\else\textdegree\fi{} where the charge scattering is zero. The experiment was performed at a momentum transfer of $q=0.44\ifmmode\times\else\texttimes\fi{}{10}^{13}$ ${\mathrm{cm}}^{\ensuremath{-}1}$ and indicate that the electric dipole moment of the electron is \ensuremath{\lesssim}${10}^{\ensuremath{-}15}$ e cm, where e is the charge of the electron.