Chiral calculations of the K→2π and K→3π weak decays

Summary

We show in many chiral schemes how to relate consistently K→2π to K to vacuum transitions. Then we discuss how the observed scale of ΔI=1/2 enhancement is set by charmed quark or charmed D-meson W-mediated loops. Lastly we demonstrate that all four K→3π decay amplitudes are linked to the above K⁰→2π transitions via PCAC and the dominant pion pole part. We conclude that all six K⁰→2π, K→3π weak decays are compatible with data.