Upper Limit of the Electric Dipole Moment of the Electron

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° where the charge scattering is zero. The experiment was performed at a momentum transfer of $q=0.44\mathrm{}\times {10}^{13}$ ${\mathrm{cm}}^{-1\mathrm{}}$ and indicate that the electric dipole moment of the electron is ≲${10}^{-15\mathrm{}}$ e cm, where e is the charge of the electron.