We discuss rare kaon decays that violate charged-lepton flavour conservation in supersymmetric theories with and without R parity, in view of possible experiments using an intense proton source as envisaged for a neutrino factory. In the Minimal Supersymmetric Standard Model, such decays are generated by box diagrams involving charginos and neutralinos, but the limits from \mu -> e \gamma, \mu-e conversion and \Delta m_K constrain the branching ratios to challengingly small values. However, this is no longer the case in R-violating theories, where such decays may occur at tree level at rates close to the present experimental limits. Within this framework, we obtain bounds on products of LL\bar{ E} and LQ\bar{ D} operators from the experimental upper limits on K^0 -> \mu^\pm e^\mp and K^{ \pm,0} -> \pi^{ \pm,0} \mu^\pm e^\mp decays. We also note the possibility of like-sign lepton decays K^\pm -> \pi^\mp \ell^\pm \ell^\pm in the presence of non-zero \tilde{ b}_L-\tilde{ b}_R mixing. We conclude that rare kaon decays violating charged-lepton flavour conservation could be an interesting signature of R violation.
Categories: hep-ph hep-ex