| In a sample of 83 x 106 BB¯ events collected by the BABAR detector, we reconstruct 310 +/- 31 B0→p-ℓ+n decays and 117 +/- 16 B+→p0ℓ+n decays. We combine the information from both channels, using isospin symmetry and the measured ratio of B lifetimes, to obtain the branching fraction BB0→p- ℓ+n=1.30 +/-0.11stat. +0.26-0.16syst. +/-FF pℓnx10 -4. With the large sample of BB¯ events available, the measurement is currently limited by systematic uncertainties in the description of background.; Based on the light-cone sum rule (LCSR) predictions for the B→pℓn form-factor, we extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vub from the measured BB0→p- ℓ+n branching fraction, VubBall01 =&parl0;3.07+0.12-0.13sta t.+0.29-0.19 syst.+/-0.08FFp ℓn+0.47 -0.43Gthy &parr0;x10-3. These results are consistent with, and of comparable precision to, existing measurements made using exclusively reconstructed decays, but have a substantially smaller statistical error. |
