The work about to be described is a continuation of an investigation begun by one of us at Princeton, New Jersey, on the scattering of electrons by gas atoms. The conditions there were so chosen that only single collisions were taken into account, and it was possible to investigate not only the energy loss on collision, as in the Franck and Hertz experiments, but also the direction of the path of the electron after collision. By employing a magnetic analysis of the velocity of the electron after impact it was found possible to obtain information as to the probability of excitation of various stationary states of the atom considered, on collision with electrons of much higher velocities than could previously be used. The curves relating scattered intensity with angle of scattering were found to have sharp maxima, which were strongly suggestive of diffraction maxima, as might be expected if the motion of electrons is governed by the wave mechanics. But whereas the wave mechanics has been eminently successful in explaining the scattering results of Davisson and Germer with single metal crystals, and of Thomson and Rupp with thin metal foils the results of Dymond have been inexplicable on this basis. It may be said at once that we have been unable to find any trace of the sharp maxima found by him in I, which were apparently due to a secondary cause. Indeed, as has recently been pointed out by Elsasser, no interference effects can be expected, when the electron loses energy on collision, the case in which Dymond found maxima, for the frequencies of the electron before and after interaction with the atom are different and there can consequently be no coherence of the scattered waves.
New interference effects from light gauge bosons in neutrino-electron scattering
