Bounds on \sin 2\beta and |V_{ub}/V_{cb}| from the Light-Quark Triangle

Abstract

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 \sin 2\beta and the ratio of |V_{ub}| to |V_{cb}|. We find that \sin 2\beta is most likely to lie in the range 0.45 \leq \sin 2\beta \leq 0.60, a result compatible very well with the present BaBar and Belle measurements. On the other hand, |V_{ub}/V_{cb}| \geq 0.8 is disfavored. Our bounds on both \sin 2\beta and |V_{ub}/V_{cb}| can soon be confronted with more precise data to be accumulated from the asymmetric B-meson factories.