DOI: 10.1140/epjc/s2003-01400-5
Hierarchical matrices in the see-saw mechanism, large neutrino mixing and leptogenesis
W. RodejohannScuola Internazionale Superiore di Studi Avanzati and INFN, Sezione di Trieste, Via Beirut 2-4, 34014 Trieste, Italy werner@sissa.it
(Received: 28 May 2003 / Revised version: 13 September 2003 / / Published online: 26 November 2003)
Abstract
We consider the see-saw mechanism for hierarchical Dirac and Majorana neutrino
mass matrices
mD and
MR, including the
CP
violating phases. Simple arguments about the structure of the neutrino mass
matrix and the requirement of successful leptogenesis lead to the situation that
one of the right-handed Majorana neutrinos is much heavier than the other two,
which in turn display a rather mild hierarchy. It is investigated how
for the
neutrino mixing one small and two large mixing angles are
generated.
The mixing matrix element
|Ue3|2 is
larger than
10-3 and a characteristic ratio between the branching ratios of
lepton flavor violating charged lepton decays
is
found.
Successful leptogenesis implies sizable
CP
violation in oscillation experiments. As in the original minimal see-saw
model, the signs of the baryon asymmetry of the universe and of the
CP
asymmetry in neutrino oscillations are equal and there is no connection
between the leptogenesis phase and the effective mass as measurable in
neutrinoless double beta decay.
© Società Italiana di Fisica, Springer-Verlag 2004
