Various definitions of minimal flavour violation for leptons

Neutrino masses imply the violation of lepton flavour and new physics beyond the Standard Model. However, flavour change has only been observed in oscillations. In analogy with the quark sector, we could deduce the existence of a principle of minimal flavour violation also for leptons Such an extension is not straightforward, since the mechanisms generating neutrino masses are unknown and many scenarios can be envisaged.. Thus, we explore some possible definitions of MFVL and propose a notion that can include many models. We build an R-parity violating neutrino mass model in agreement with our preferred definition of MFVL, and show that flavour violating processes are not necessarily controlled by the MNS mixing matrix. (c) 2006 Elsevier B.V. All rights reserved.