Ha, H (reprint author), Korea Univ, Seoul, South Korea.
We present a measurement of the charmless semileptonic decay B-0 -> pi(-) l(+) nu using a data sample containing 657 x 10(6) B (B) over bar events collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider operating near the Y(4S) resonance. We determine the total branching fraction of the decay, B(B-0 -> pi(-) l(+) nu) = (1.49 +/- 0.04(stat) +/- 0.07(syst)) x 10(-)4. We also report a new precise measurement of the differential decay rate and extract the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar using model-independent and model-dependent approaches. From a simultaneous fit to the measured differential decay rate and lattice QCD results, we obtain vertical bar V-ub vertical bar (3.43 +/- 0: 33) x 10(-3), where the error includes both experimental and theoretical uncertainties.