  Assuming only a hierarchical structure of the heavy Majorana neutrino masses
and of the neutrino Dirac mass matrix m_D of the see-saw mechanism, we find
that in order to produce the observed baryon asymmetry of the Universe via
leptogenesis, the scale of m_D should be given by the up-quark masses. Lepton
flavor violating decays \mu \to e + \gamma, \tau \to \mu + \gamma and \tau \to
e + \gamma are considered and a characteristic relation between their decay
rates is predicted. The effective Majorana mass in neutrinoless double beta
decay depends on the CP violating phase controlling the leptogenesis if one of
the heavy Majorana neutrinos is much heavier than the other two. Successful
leptogenesis requires a rather mild mass hierarchy between the latter. The
compatibility of this hierarchical see-saw model with the low energy neutrino
mixing phenomenology requires that the mixing angle limited by the CHOOZ and
Palo Verde experiments should be relatively large, \sin^2\theta_3 \gtap 0.01.
The CP violation effects in neutrino oscillations can be observable. In
general, there is no direct connection between the latter and the CP violation
in leptogenesis. If the CP violating phases of the see-saw model satisfy
certain relations, the baryon asymmetry of the Universe and the rephasing
invariant J_{CP} which determines the magnitude of the CP violation effects in
neutrino oscillations, depend on the same CP violating phase and their signs
are correlated.
