Georg Viehhauser

Abstract:

A search for the lepton-family-number-violating decays [Formula presented] and [Formula presented] has been performed using CLEO II data. No evidence of a signal has been found and the corresponding upper limits are [Formula presented] and [Formula presented] at 90% C.L. © 1997 The American Physical Society.

Abstract:

We have searched for lepton flavor violating decays of the τ lepton using final states with an electron or a muon and one or two π⁰ or η mesons but no neutrinos. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.68 fb⁻¹. No evidence for signals was found, resulting in much improved limits on the branching fractions for the one-meson modes and the first upper limits for the two-meson modes. © 1997 The American Physical Society.

Abstract:

We have searched for the decay of the [Formula presented] lepton into seven charged particles and zero or one [Formula presented]. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.61 [Formula presented]. No evidence for a signal is found. Assuming all the charged particles are pions, we set an upper limit on the branching fraction [Formula presented] at the 90% confidence level. This limit represents a significant improvement over the previous limit. © 1997 The American Physical Society.

Abstract:

Using the CLEO-II data set we have searched for the decays B⁰→D^(*)+D^(*)-. We observe one candidate signal event for the decay B⁰→D^*+D^*- with an expected background of 0.022±0.011 events. This yield corresponds to a branching fraction of B(B⁰→D^*+D^*-)=[5.3^+7.1-3.7(stat)±1.0(syst)]×10^-4 and an upper limit of B(B⁰→D^*+D^*-)<2.2×10^-3 at the 90% C.L. We see no significant excess of signal above the expected background level in the other modes, and we calculate the 90% C.L. upper limits on the branching fractions to be B(B⁰→D^*±D^*∓)<1.8×10^-3 and B(B⁰→D⁺D^-)<1.2×10^-3. © 1997 The American Physical Society.

Abstract:

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio [Formula presented] for the mean charged multiplicity observed in [Formula presented] events, [Formula presented], to the mean charged multiplicity observed in [Formula presented] events, [Formula presented]. We find [Formula presented] [Formula presented] for jet-jet masses less than 7 GeV. © 1997 The American Physical Society.