K_L -> pi0 gamma e+ e- and its relation to CP and chiral tests

Abstract

The decay K_L -> pi0 gamma e+ e- occurs at a it higher rate than the nonradiative process K_L -> pi0 e+ e-, and hence can be a background to CP violation studies using the latter reaction. It also has an interest in its own right in the context of chiral perturbation theory, through its relation to the decay K_L -> pi0 gamma gamma. The leading order chiral loop contribution to K_L -> pi0 gamma e+ e-, including the [q(e+) + q(e-)]^2/m^2(pi) dependence, is completely calculable. We present this result and also include the higher order modifications which are required in the analysis of K_L -> pi0 gamma gamma.