VECTOR-MESON EXCHANGE CONTRIBUTIONS TO K-]PI-GAMMA-GAMMA AND K-L-]GAMMA-L(-)()L()

We have studied in the framework of Chiral Perturbation Theory (chi PT ) the O(p(6)) vector meson contributions to K --> pi gamma gamma and K -L --> gamma gamma. We construct the most general chi PT Lagrangian f or the weak vector-pseudoscalar-photon (VP gamma) vertex for K --> pi gamma gamma and K-L --> gamma gamma and consequently we get the full structure of the O(p(6)) local contributions generated by vector meson exchange. We then compute new factorizable contributions to the weak VP gamma vertex generated by the odd-intrinsic parity violating Lagran gian with no additional couplings. We find in fact a very nice agreeme nt with the phenomenology of K --> pi gamma gamma and K-L --> gamma ga mma, more predictive power and a deeper understanding of the O(p(6)) local operators. A novel interpretation of the K-L --> gamma gamma da ta is given, Also a comparison with the existing models is presented. (C) 1997 Elsevier Science B.V.