Towards the low energy frontier

Unanswered and interesting questions arise in the leptonic sector of the standard model of particle physics: Are there new sources of CP violation? Are the neutrinos Dirac or Majorana particles? Are there more than one Higgs doublet that modify the leptonic or semileptonic decays of mesons? All these questions may be answered by a detailed study of low energy experiments. In this talk we present a short review of some examples where using present or future data on D meson decays, neutrino scattering on electron or coherent scattering on nucleus and neutrinos produced in accelerators may help us to answer those questions. (paper)