PQCD ANALYSIS OF EXCLUSIVE CHARMLESS B-MESON DECAY SPECTRA

We apply the perturbative QCD formalism, including Sudakov effects, to exclusive charmless semi-leptonic B meson decays. Predictions for bot h the charged lepton and lepton pair invariant mass spectra of the B - -> pi lambda nu and B --> rho lambda nu, decays in the large recoil re gion are presented. After combining soft pion results, we extract \V-u b\ less than or equal to 4.5 x 10(-3) from current CLEO data. With our predictions, future data will not only provide a more precise extract ion of \V-ub\, but also test perturbative QCD in B meson decays.