SELECTION RULES IN REACTIONS INVOLVING POLARIZED PARTICLES

Simon and Welton¹ and Shirokov² have obtained the selection rules for a reaction of the type a + b → c + d in the form of relations between the polarization vectors and tensors. They assume that the initial state is not polarized. The present communication gives a derivation of the selection rules for any arbitrarily-polarized initial state. We shall use Shirokov's notation² and assume that all the particles have nonvanishing rest mass…