  New mixing structures between chiral generations of elementary particles at
low energy are shown in a vectorlike model with a horizontal symmetry SU(1,1).
In this framework the chiral model including odd number chiral generations is
realized via the spontaneous symmetry breaking of the horizontal symmetry. It
is shown that the Yukawa coupling matrices of chiral generations have naturally
hierarchical patterns, and in some cases the overall factors of their Yukawa
coupling matrices, e.g. the Yukawa coupling constants of the bottom quark and
tau lepton are naturally suppressed.
