ON THE STRUCTURE OF INTERACTIONS
Hiroomi Umezawa · Progress of Theoretical Physics · 1959
There are two ways of approaching the theory of elementary particles: One is to classify interactions according to their theoretical behaviors and another is to look into various systematics governing the interactions realized in experiments. An effort is made to combine both in suggesting many strata which seem to exist in the structure of elementary particles. A section is devoted to a theoretical classification of interactions. The strong interactions are briefly discussed, and experiments on weak interactions and their theoretical analysis are reviewed. Some features of the suggested strata which seem to play essential roles in extremely high energy phenomena are discussed. (auth)