Two-electron interference in the helium (e, 2e) differential cross section at 64.6 eV

Abstract

The unexpected sharp dip which is known to exist in the helium (e, 2e) differential cross section at an incident electron energy of 64.6 eV, and for equal energies and angles of the two outgoing electrons, is known to be sensitive to three of the four available experimental parameters. We have now investigated the sensitivity of the dip to the fourth parameter, the asymmetry of the angles of the outgoing electrons, and have found that the dip exists over a wide range of asymmetric angles, but with an almost constant angle between the two electrons. A two-electron interference model is proposed to explain these results.