ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2011, vol. 83, p. -
Measurement of the decay B0→π-ℓ+ν and determination of |Vub|
We present a measurement of the charmless semileptonic decay B0→π-ℓ+ν using a data sample containing 657×106 BB̄ events collected with the Belle detector at the KEKB asymmetric-energy e+e- collider operating near the Υ(4S) resonance. We determine the total branching fraction of the decay, B(B0→π-ℓ+ν)=(1.49±0.04(stat) ±0.07(syst))×10-4. We also report a new precise measurement of the differential decay rate and extract the Cabibbo-Kobayashi- Maskawa matrix element |Vub| using model-independent and model-dependent approaches. From a simultaneous fit to the measured differential decay rate and lattice QCD results, we obtain |Vub|=(3.43±0. 33)×10-3, where the error includes both experimental and theoretical uncertainties. © 2011 American Physical Society.