KL--> pi 0l+l- decays for large mt.

Abstract

We discuss the decays K/sub L/..--> pi../sup 0/l/sup +/l/sup -/ when m/sub t/ is large. Unlike the case of K/sub L/..--> pi pi.., 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 a Z or two W's as well as from those with a photon and a W are important when m/sub t/approx. >M/sub W/.