CP violation in the K L→ π0ℓ +ℓ − decay amplitude for large mt

Abstract

We discuss CP violation in the amplitude for K L→ π 0ℓ +ℓ − when m t is large. Unlike the case of K L→ ππ, CP violation in the decay amplitude itself is comparable to that which comes from the mass matrix. We study the CP violating effects, including strong interaction (QCD) corrections to the amplitudes which arise from one-loop diagrams. Short-distance contributions from diagrams that involve a W and Z or two W's as well from those with a photon and a W are important when m t ⪆M W .