SOME COMMENTS AND A PREDICTION CONCERNING DECAY K2O-] GAMMAGAMMA

It is shown how only pseudoscalar (π0,η) and vector (K* (6)) poles need be considered in a pole-model analysis of the decay K20→γγ. The calculation of the decay amplitude is presented in detail, both in an SU(3)-symmetric model of VVP couplings with φω mixing, and in a model (due to Arnowitt et al.) of PCAC breakdown with partial SU(3) symmetry, which fits the decay rates of π0→γγ and η→γγ reasonably well. It is found that the pseudoscalar and vector contributions add, instead of partially canceling as claimed by earlier workers, so that theory and experiment are no longer in reasonable agreement. Moreover, a separate calculation of the important vector pole contribution to the decay amplitude in the free-field quark model yields no significant diminution of its SU(3) magnitude. © 1969 The American Physical Society.