Poincaré and TCP invariance in the determination of wave equations for particles of arbitrary spin

Abstract

A brief outline is given of different types of approaches to the derivation of relativistic wave equations for free particles of arbitrary mass m and spin s. It is pointed out that all such equations can be subsumed in a standard form involving wavefunctions transforming according to the representation D(0,s)⊕D(s,0) of the Lorentz group. Generalizing earlier work employing this standard form, we determine all such equations (in a standard form) which are invariant under the Poincaré group and the combined operation θ = TCP. It is shown that the resulting equations are automatically invariant under T, C, and P separately.