We report a measurement of the branching fraction ratios R(D ( * ) ) ofB → D ( * ) τ −ν τ relative tō B → D ( * ) −ν (where = e or µ) using the full Belle data sample of 772 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. The measured values are R(D) = 0.375 ± 0.064(stat.) ± 0.026(syst.) and R(D * ) = 0.293 ± 0.038(stat.) ± 0.015(syst.). The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic τ decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction.
We report new measurements of the total cross sections for e + e − → Υ(nS)π + π − (n = 1, 2, 3) and e + e − → bb from a high-luminosity fine scan of the region √ s = 10.63-11.05 GeV with the Belle detector. We observe that the Υ(nS)π + π − spectra have little or no non-resonant component and extract from them the masses and widths of Υ(10860) and Υ(11020) and their relative phase. We find M10860 = (10891.1 ± 3.2 +0.6 −1.7) MeV/c 2 and Γ10860 = (53.7 +7.1 −5.6 +1.3 −5.4) MeV and report first measurements M11020 = (10987.5 +6.4 −2.5
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