Parity Violation Effects Induced by Neutral Currents in Atoms

Abstract

The problem of space reflexion symmetry in atomic physics is a long story which began with the Wigner explanation of the Laporte rule. The symmetry was not questioned until the discovery of parity violation in weak interactions, following the brilliant analysis of Lee and Yang (1). In 1958, Zel’dovich (2) gave the first discussion of the possible effects in Atomic Physics of a weak electron-nucleon interaction induced by neutral currents. In particular, he estimated the rotation of the plane of polarization of visible light propagating in optically inactive matter to be of the order of 10−13 radian/meter, and, at that time, his conclusion was that such an effect, obviously, could not be observed. A similar investigation, somewhat more detailed, was performed later by F.C. Michel (3); the predicted effects concerning mainly the Hydrogen atom, were also not very encouraging.