π0→2γ Decays in Relativistic Composite Models

Abstract

Various theories on the radiative decay of neutral pions are critically re-examined. It is shown that, among the variety of `quark' models, the single triplet model or the three-triplet model is the best candidate over other subhadronic models. The sign of the decay amplitude can be fixed unambiguously by the use of relativistic composite theory in the vector dominance approximation with different views and conclusions from that of Okubo's analysis. We have generalized the method developed by Kitazoe and Teshima and Sharpened their arguments, thereby obtaining some new results. These suggest rather definitely the necessity of departure from nonrelativistic descriptions of composite models.