II. An equation for a particle with two mass states and positive charge density

Abstract

A relativistic wave equation in the canonical form (2) is given which describes a particle having two different rest masses. In one mass state the particle has a spin 3/2, in the other a spin 1/2. The free charge density is positive definite so that the equation can be quantized in the usual manner in accordance with the exclusion principle. The equation is irreducible. This example establishes the principle that irreducible multi-mass equations exist which can be used to form the basis of a physical theory along the usual lines, contrary to the general prevalent view.