Lepton-flavor mixing and K → πυ(υ)over-bar decays

The impact of possible sources of lepton-flavor mixing on K --> pinu(nu) over bar decays is analysed. At the one-loop level lepton-flavor mixing originated from non-diagonal lepton mass matrices cannot generate a CP-conserving K-L --> pi(0)nu(nu) over bar amplitude. The rates of these modes are sensitive to leptonic flavor violation when there are at least two different leptonic mixing matrices. New interactions that violate both quark and lepton universalities could enhance the CP-conserving component of Gamma(K-L --> pi(0)nu(nu) over bar) and have a substantial impact. Explicit examples of these effects in the context of supersymmetric models, with and without R-parity conservation, are discussed. (C) 2004 Elsevier B.V All rights reserved.