Measurement of vertical bar V-ub vertical bar from Inclusive Charmless Semileptonic B Decays

We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the Cabibbo-Kobayashi-Maskawa matrix element vertical bar V-ub vertical bar, using a multivariate analysis method to access similar to 90% of the B -> X(u)l nu phase space. This approach dramatically reduces the theoretical uncertainties from the b-quark mass and nonperturbative QCD compared to all previous inclusive measurements. The results are based on a sample of 657 X 10(6) B (B) over bar pairs collected with the Belle detector. We find that Delta B(B -> X(u)l nu; p(l)*(B) > 1.0 GeV/c) = 1.963X(1 +/- 0.088(stat) +/- 0.081(syst)) X 10(-3). Corresponding values of vertical bar V-ub vertical bar are extracted using several theoretical calculations.We thank the KEKB group for excellent operation of the accelerator, the KEK cryogenics group for efficient solenoid operations, and the KEK computer group and the NII for valuable computing and SINET3 network support. We acknowledge support from MEXT, JSPS and Nagoya's TLPRC (Japan); ARC and DIISR (Australia); NSFC (China); DST (India); MOEHRD and KOSEF (Korea); MNiSW (Poland); MES and RFAAE (Russia); ARRS (Slovenia); SNSF (Switzerland); NSC and MOE (Taiwan); and DOE (USA)