Abstrakt
The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element Vub using inclusive and exclusive decays is performed with the full Belle data set at the ϒð4SÞ resonance, corresponding to an integrated luminosity of 711 fb−1.We analyze collision events in which one
B meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic Xu system of the semileptonic b → ul¯νl decay. We separate exclusive B → πl¯νl decays from other inclusive
B → Xul¯νl and backgrounds with a two-dimensional fit that utilizes the number of charged pions in the Xu system and the four-momentum transfer q2 between the B and Xu systems. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the B → πl¯νl form factor, we determine jVexcl ub j ¼ ð3.78 0.23 0.16 0.14Þ × 10−3 and jVincl ub j ¼ ð3.88 0.20 0.31 0.09Þ × 10−3, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of jVexcl ub j=jVincl ub j ¼ 0.97 0.12 is compatible with unity.