CPviolation in the time evolution of the decayK0→π0e+e−

We examine the possibility of extracting CP-violating terms in the decay ${\mathit{K}}^0$→${\mathrm{\pi }}^0$ ${\mathit{e}}^{+}$ ${\mathit{e}}^{\mathrm{-}}$ by studying the time evolution of a ${\mathit{K}}^0$ beam. We focus on the interference region and search for clear effects. We find that experiments which average over the electron and positron momenta can detect CP violation as an oscillation in the decay rate. The branching ratio is (3–5)×${10}^{\mathrm{-}12}$ and direct CP violation dominates over a wide range of the parameters.