  The comprehensive analyses are presented in the model with the inverted mass
hierarchy for neutrinos, which follows from a geometrical structure of a (1+5)
dimensional space-time where two extra dimensions are compactified on the
T^2/Z_3 orbifold. The model gives two large lepton flavor mixings due to the S3
structure in the (1+5) dimensional space-time. It also predicts the lightest
neutrino mass as m_3=(1-50)\times 10^{-5}eV and the effective neutrino mass
responsible for neutrinoless double beta decays as <m>_{ee}\simeq 50 meV. The
low energy CP violation, J_{CP} could be 0.02. On the other hand, the observed
baryon asymmetry in the present universe is produced by the non-thermal
leptogenesis, which works even at the reheating temperature
TR=10^{4}-10^{6}GeV. The correlation between the baryon asymmetry and the low
energy CP violation is examined in this model.
