Semileptonic Decays at Belle

Abstract

We present three analyses based on data samples collected by the Belle detector at the KEKB e+e- asymmetric energy collider. The first one contains the measurement of the branching fractions and q^2 distributions of exclusive charmless semileptonic B decays, which are used to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{ub}|. The sample of events is obtained by fully reconstructing one of the B mesons in selected hadronic modes. The second analysis determines the branching fraction and the form factors rho^2, R_1 and R_2 for the exclusive decay B^0 -> D^{*-} \ell^+ \nu. These measurements are used to extract the Cabibbo-Kobayashi-Maskawa matrix element |V_{cb}|. The third analysis investigates B -> D^{**} \ell \nu decays and determines branching ratios for the four modes D_{0}^{*}, D_{1}, D_{1}^{'} and D_{2}^{*} for both charged and neutral B decays.