VECTOR DOMINANCE EFFECTS IN WEAK RADIATIVE DECAYS OF B-MESONS

The long-distance vector-meson-dominance (VMD) effects on the weak radiative decays B and B D*00 are studied. For B decays, the VMD contribution is (10 20)% of the short-distance penguin amplitude. The pole effect is as important as the VMD one in the decay B- -, but it is suppressed in B 00. The branching ratio of B, estimated to be of order 10-6, strongly depends on the sign of the Wolfenstein parameter. A measurement of any deviation of the ratio R= (B- -)/ (B 00) away from the isospin value 2 will provide a probe on the long-range contribution and possibly indicate the sign of: R>2 for <0 and R 2 for >0. The decay B D*00 does not receive short-distance contributions, and its branching ratio, predicted to be 0.9×10-6, is dominated by W exchange accompanied by a photon emission. © 1995 The American Physical Society.