K→πνν¯ and new physics in the neutrinos

Abstract

Abstract We discuss generic effects of new physics on the rare decay modes K L → π 0 ν ν ¯ and K + → π + ν ν ¯ from the point of view of the neutrino sector. We pay particular attention to the cases of right handed neutrino couplings and neutrino lepton flavour violating interactions. The first of these examples requires the existence of a new light (sterile) right-handed neutrino and its contribution to both rates is always additive to the standard model. It is motivated as a possible solution to the so called charged B anomalies. The case of neutrino lepton flavour violating couplings produces interesting constraints on new physics which are competitive with those from standard searches for charged lepton flavour violating in kaons and in some cases better than those from tau decay.