Exclusive B -> Ml(+)l(-) (M = pi, K, rho, K*) decays and determinations ofvertical bar V-ts vertical bar (and vertical bar V-td/V-ts vertical bar)

We examine the possibility for precise determination of /V-ts/ (and /V-td/V -ts/) from the exclusive decays, B --> Kl(+)l(-), B --> K*l(+)l(-) (and B - -> pi l(+)l(-), B --> rho l(+)l(-)). We show that the ratio /V-ts/ can be e xtracted experimentally with a small theoretical uncertainty from hadronic form-factors, if we appropriately constrain kinematical regions of q(2). We also give detailed analytical and numerical results on the differential de cay width d Gamma(B --> K*l(+)l(-))/dq(2), and the ratios of integrated bra nching fractions, B(B --> rho l(+)l(-))/B(B --> K*l(+)l(-)). We estimate th at one can determine the ratio /V-ts/ from those decays within theoretical accuracy of similar to 10%. (C) 1998 Elsevier Science B.V. All rights reser ved.