Exclusive Weak Decays of B–Mesons

We present the results of a detailed study of semi-leptonic and nonleptonic weak decays of B-mesons based on the spin-flavor symmetry for heavy quarks. Semi-leptonic and transitions are discussed in an essentially model-independent way. In particular, a rather precise value for Vcb, is obtained, as well as a prediction for the entire set of form factors for all accessible values of q2. This information is used to obtain improved predictions for exclusive nonleptonic decays. We discuss the factorization hypothesis and various tests of it, and show how yet unknown decay constants may be determined from nonleptonic decays.