Bounds on sin2β and |Vub/Vcb| from the light-quark triangle

With the help of the light-quark triangle, which is essentially congruent to the rescaled unitarity triangle for a variety of textures of the quark mass matrices, we calculate the CP-violating quantity sin2β and the ratio of |Vub| to |Vcb|. We find that sin2β is most likely to lie in the range 0.45⩽sin2β⩽0.60, a result compatible very well with the present BaBar and Belle measurements. On the other hand, |Vub/Vcb|⩾0.8 is disfavored. Our bounds on both sin2β and |Vub/Vcb| can soon be confronted with more precise data to be accumulated from the asymmetric B-meson factories.