On the rare $K \to \pi \bar l l$ decays

Abstract

In this talk, we present our recent work on the $K\ra\pi \bar{l} l$ decays in a combined framework of chiral perturbation theory and Large--$N_c$ QCD under the dominance of a minimal narrow resonance structure. The proposed description reproduces very well the experimental Br$(K^+\ra\pi^+ e^+ e^-)$ and Br$(K_S\ra\pi^0 e^+ e^-)$. Predictions for the $K\ra\pi \mu^{+}\mu^{-}$ modes are also obtained and we can conclude to the constructive type for the interference between the {\it direct} and {\it indirect} CP--violation amplitudes in $K_L\ra\pi^0 e^+ e^-$.