Georg Viehhauser

Abstract:

Using 4.8 fb^-1 of data taken with the CLEO II detector, the branching fraction for the Cabibbo suppressed decay D⁺ → π⁰ℓ⁺v measured relative to the Cabibbo favored decay D⁺ → K⁰̄ℓ⁺v is found to be 0.046 ± 0.014 ± 0.017. Using Vcs and Vcd from unitarity constraints, we determine |f^π+(0) / f^K+(0)|² = 0.9 ± 0.3 ± 0.3 We also present a 90% confidence level upper limit for the branching ratio of the decay D⁺ → ηe⁺ve relative to that for D⁺ →⁰e⁺ve of 1.5. © 1997 Published by Elsevier Science B.V.

Abstract:

We have measured the spectral shape Michel parameters ρ and η using leptonic decays of the τ, recorded by the CLEO II detector. Assuming e - μ universality in the vectorlike couplings, we find ρeμ = 0.735 ± 0.013 ± 0.008, where the first error is statistical and the second systematic. We also present measurements for the parameters for e and μ final states separately. © 1997 The American Physical Society.

Abstract:

We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B⁰ → D*^- l⁺v̄. This spectrum, measured with 2.38 fb^-1 of data collected at the Y(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Y(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B⁰ and B⁺ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B⁺ and B⁰ pairs at the Y(4S). We report b+/b0 = 0.950^+0.117-0.080 ± 0.091, b0 = (10.78 ± 0.60 ± 0.69)%, and b+ = (10.25 ± 0.57 ± 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, τ+/τ0. © 1997 Published by Elsevier Science B.V.

Abstract:

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we present new measurements of the branching fractions for D⁺→KSK⁺ and D⁺ → KSπ⁺. These results are combined with other CLEO measurements to extract the ratios of isospin amplitudes and phase shifts for D→KK and D→Kπ. © 1997 The American Physical Society.

Abstract:

Using the CLEO II detector at the Cornell Electron Storage Ring operated at [Formula presented] we have determined the Michel parameters ρ, ξ, and δ in [Formula presented] decay as well as the τ neutrino helicity parameter [Formula presented] in [Formula presented] decay. From a data sample of [Formula presented] produced τ pairs we analyzed events of the topologies [Formula presented] and [Formula presented] We obtain [Formula presented] [Formula presented] [Formula presented] and [Formula presented] where we have used the previously determined sign of [Formula presented] [ARGUS Collaboration, H. Albrecht et al., Z. Phys. C 58, 61 (1993); Phys. Lett. B 349, 576 (1995)]. We also present the Michel parameters as determined from the electron and muon samples separately. All results are in agreement with the standard model [Formula presented] interaction. © 1997 The American Physical Society.