Exclusive Semileptonic and Rare B Meson Decays in QCD

We present first complete results for the semileptonic and rare radiative form factors of $ mesons weak decay into a light vector meson (rho, omega, K*, phi) in the light-cone sum rule approach. The calculation includes radiative corrections, higher twist corrections and SU(3) breaking effects. The theoretical uncertainty is investigated in detail. A simple parametrization of the form factors is given in terms of three parameters each. We find that the form factors observe several relations inspired by heavy quark symmetry.