The Unitarity Triangle on the First Quadrant and the Quark Mass Matrices   in the Nearest-Neighbor Interaction Basis
  The unitarity triangle on the first quadrant in the $\rho -\eta$ plane is discussed in the framework of the quark mass matrices in the NNI basis. If the quark mass matrices of the up-type is the Fritzsch one and the down-type is the one proposed by Branco et al., respectively, one gets the unitarity triangle with the vertex on the first quadrant. This simple model may be a candidate of the quark mass matrix ansatze, if the allowed region of the vertex of the unitarity triangle is restricted in the first quadrant by future experiments. 
Toshiaki Ito (Nagoya University)