DETERMINATION OF VERTICAL-BAR-V-TS-VERTICAL-BAR FROM D-]K-ASTERISK-L-NU AND B-]K-ASTERISK-GAMMA DATA VIA HEAVY-QUARK SYMMETRY AND PERTURBATIVE QCD

We use heavy quark effective theory (HQET) and perturbative QCD to study the heavy-meson-light-vector-meson transitions involved in D and B decays. HQET is used to relate the measured D --> K*lv vector and axial-vector form factors at four-momentum transfer q(2) = 0 to the B --> K*gamma tenser and axial-tenser form factors at q(2) = 16.5 GeV2. Perturbative QCD is then used to find matching conditions for the B-meson form factors at q(2) = 0, A five parameter ''vector-dominance''-type fit of the two HQET form factors, consisting of single pole, double pole, and subtraction terms, is used to match the data at q(2) = 16.5 GeV2 to QCD at q(2) = 0. The values at q(2) = 0 are compared with recent data on the exclusive rate for B --> K*gamma decay to extract a value for the Cabibbo-Kobayashi-Maskawa matrix element \V-ts\ = 0.026, with 23% experimental uncertainty, and 29% theoretical uncertainty from higher order QCD effects and violations of heavy quark symmetry.