Exclusive semileptonic and rareBmeson decays in QCD

We present the first complete results for the semileptonic and rare radiative form factors of the $B$ meson’s 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.