Neutrino physics in the seesaw model

The seesaw model of heavy and light Majorana neutrinos and its low-energy effective theory are studied. when the number of heavy neutrinos is equal to or less than the number of light lepton generations. We establish a general relationship between the high-energy parameters and the low-energy observables involving only the light fields. It is shown how low-energy measurements of the properties of light neutrinos suffice a priori to determine all couplings of the unobserved heavy neutrinos. CP violation is present in low-energy processes if seesaw-model leptogenesis creates the matter-antimatter asymmetry of the universe. (C) 2003 Elsevier B.V. All rights reserved.