Georg Viehhauser

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.

Abstract:

The branching fractions for [Formula presented] [Formula presented] and [Formula presented] are measured using data collected with the CLEO detector at the CESR [Formula presented] collider: [Formula presented]=0.1776[Formula presented]0.0006[Formula presented]0.0017, [Formula presented]=0.1737[Formula presented]0.0008[Formula presented]0.0018, and [Formula presented]=0.1152[Formula presented]0.0005[Formula presented]0.0012, where the first error is statistical, the second systematic, and [Formula presented] refers to either a charged [Formula presented] or [Formula presented]. Also measured is the [Formula presented] mass, [Formula presented]=(1778.2[Formula presented]1.4) MeV. Lepton universality is affirmed by the relative branching fractions [Formula presented]/[Formula presented]=0.9777[Formula presented]0.0063[Formula presented]0.0087, [Formula presented]/[Formula presented]=0.6484[Formula presented]0.0041[Formula presented]0.0060) and the charged-current gauge coupling-constant ratios [Formula presented]=1.0026[Formula presented]0.0055, [Formula presented]=0.9990[Formula presented]0.0098). The [Formula presented] mass result may be recast as a [Formula presented] neutrino mass limit, [Formula presented]60 MeV at 95% C.L. © 1997 The American Physical Society.