Bounds on sin 2β 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 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 less than or equal to sin 2 beta less than or equal to 0.60, a result compatible very well with the present BaBar and Belle measurements. On the other hand, \V-ub/V-cb\ greater than or equal to 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. (C) 2001 Elsevier Science B.V. All rights reserved.