Predictions on B ->pi(l)over-bar-nu(l), D ->pi(l)over-bar-nu(l), and D -> K(l)over-bar-nu(l) from QCD light-cone sum rules - art. no. 114002

The f(+) form factors of the B-->pi, D-->pi and D-->K transitions are calcu lated from QCD light-cone sum rules (LCSRs) and used to predict the widths and differential distributions of the exclusive semileptonic decays B-->pi( l) over bar nu (l), D-->pi(l) over bar nu (l) and D-->K (l) over bar nu (l) , where l = e,mu. The current theoretical uncertainties are estimated. The LCSR results are found to agree with the results of lattice QCD calculation s and with experimental data on exclusive semileptonic D decays. Comparison of the LCSR prediction of B-->pi(l) over bar nu (l) with the CLEO measurem ent yields a value of \V-ub\ in agreement with other determinations.