Aubert, B. et al. (2008) Measurements of Partial Branching Fractions for B¯→Xulν¯ and Determination of |Vub|. Physical Review Letters, 100 (17). p. 171802. ISSN 0031-9007

We present partial branching fractions for inclusive charmless semileptonic B decays B̅ →Xuℓν̅ , and the determination of the Cabibbo-Kobayashi-Maskawa matrix element |Vub|. The analysis is based on a sample of 383×106 Υ(4S) decays into BB̅ pairs collected with the BABAR detector at the SLAC PEP-II e+e- storage rings. We select events using the invariant mass MX of the hadronic system, the invariant mass squared, q2, of the lepton and neutrino pair, the kinematic variable P+, or one of their combinations. We then determine partial branching fractions in limited regions of phase space: ΔB=(1.18±0.09stat±0.07syst±0.01theor)×10-3 (MX<1.55  GeV/c2), ΔB=(0.95±0.10stat±0.08syst±0.01theor)×10-3 (P+<0.66  GeV/c), and ΔB=(0.81±0.08stat±0.07syst±0.02theor)×10-3 (MX<1.7  GeV/c2, q2>8  GeV2/c4). Corresponding values of |Vub| are extracted using several theoretical calculations.

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