CP-violating decay K/sub L/ yields π0ν nu-bar

The process K/sub L/0 yields π0ν nu-bar offers perhaps the clearest window yet proposed into the origin of CP violation. The largest expected contribution to this decay is a direct CP-violating term at ∼few x 10/sup -12/. The indirect CP-violating contribution is some 3 orders of magnitude smaller, and CP-conserving contributions are also estimated to be extremely small. Although this decay has never been directly probed, a branching ratio upper limit of approximately 1% can be extracted from previous data on K/sub L/0 yields 2π0. This leaves an enormous range in which to search for new physics. If the Kobayashi-Maskawa (KM) model prediction can be reached, a theoretically clean determination of the KM product sinθ2sinθ3sinδ can be made