The CP-violating asymmetry in KL→π+π−e+e−

We update the theoretical analysis of the CP-violating asymmetry in the decay KL→π+π−e+e−, relying on chiral perturbation theory and on the most recent phenomenological information. With the experimentally determined magnetic amplitude and branching ratio as input, the asymmetry can be calculated with good accuracy. The theoretical interpretation of the sign of the asymmetry is discussed.