A symmetry pattern of maximal CP violation and a determination of the unitarity triangle

Within a specific texture of the quark mass matrix the notion of a maximal violation of the CP symmetry can be defined. The experimental constraints from weak decays imply that in reality one is close to the case of maximal CP violation, which vanishes as the mass of the u-quark approaches zero. The unitarity triangle of the Cabibbo-Kobayashi-Maskawa matrix elements is determined. It is related to the triangle relating the Cabibbo angle to the quark mass ratios in the complex plane. The angle α describing the CP violation in the decay Bd → π+ π− is close to 90°.