THE NATURE OF THE FOUR-FERMION INTERACTION

Abstract

The near equality of the effective coupling constants in the processes of beta decay, muon decay and muon capture has led to the postulation of a Universal Fermi Interaction between the pairs of spinor fields np, l.tI/, ev. The weak decays of the strange particles are consistent with an effective coupling constant of the same order of magnitude and can be understood by adding the A ° -p pair to the above pairs of spinors. The possibility of a universal four-fermion interaction has been reexamined in the light of the. recent experimental results on the nonconservation of parity and charge conjugation in weak interactions. From measurements on beta, muon, pion and kaon decay and the assumptions of the two-component neutrino and the law of conservation of leptons, it is concluded that the only possible universal fourfermion interaction is an equal admixture of vector plus axial vector interaction. Several experiments appear to contradict this hypothesis and their status is reexamined .