K20→γγDecay in a Current-Current Quark Model

The fermion-loop model introduced by Steinberger to explain the decay ${\pi }^0\to \gamma \gamma$ is suitably modified for weak interactions so that it provides a qualitative explanation for ${K_2}^0\to \gamma \gamma$ as well. The weak Hamiltonian is phenomenologically constructed from the one-baryon octet matrix elements of the symmetric quark model. Since these parameters are fitted to the nonleptonic decay of hyperons, this is a model for ${K_2}^0\to \gamma \gamma$ with no adjustable parameters.