Georg Viehhauser

Abstract:

We present a study of three B⁰ decay modes useful for time-dependent CP asymmetry measurements. From a sample of 9.7×10⁶ BB̄ meson pairs collected with the CLEO detector, we have reconstructed B⁰ →J/ψKS⁰, B⁰→χclKS⁰, and B⁰→J/ψπ⁰ decays. The latter two decay modes have been observed for the first time. We describe a KS⁰→π⁰π⁰ detection technique and its application to the reconstruction of the decay B⁰ →J/ψKS⁰. Combining the results obtained using KS⁰→π⁺π^- and KS⁰→π⁰π⁰ decays, we determine B(B⁰ →J/ψK⁰)=(9.5±0.8±0.6)×10^-4, where the first uncertainty is statistical and the second one is systematic. We also obtain B(B⁰→χclK⁰)=(3.9-1.3 ^+1.9±0.4)×10^-4 and B(B⁰→J/ψπ⁰)=(2.5-0.9 ^+1.1±0.2)×10^-5. ©2000 The American Physical Society.

Abstract:

The decays B⁰→D*⁺D*^-, B⁰→D*±D∓ and B⁰→D⁺D^- are studied in 9.7 X 10⁶ γ(4S)→BB̄ decays accumulated with the CLEO detector. We determine B(B⁰→D*⁺D*^-) = (9.9^+4.2-3.3[stat]±1.2[syst]) X 10^-4 and limit B(B⁰→D*^±D ^∓)<6.3X10^-4 and B(B⁰→D⁺D^-)<9.4 X 10^-4 at 90% confidence level (C.L.). We also perform the first angular analysis of the B⁰→D*⁺D*^- decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% C.L. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays. ©2000 The American Physical Society.

Abstract:

Searches for CP violation in decays of B mesons to three Kπ modes, K^±π^±, K^±π⁰, KS⁰π^±, the mode K^±η′, and the vector-pseudoscalar mode ωpi^±. These decay modes have well-measured branching ratios and significant signal yields and are self-tagging. Any possible systematic bias on charge asymmetries is negligible compared to the statistical measurement errors. The dependence of the likelihood function on the charge asymmetry for each of the five decay modes is described. All five modes showed no evidence for CP violation.

Abstract:

We report on a study of the invariant mass spectrum of the hadronic system in the decay τ^-→π^-π⁰ντ. This study was performed with data obtained with the CLEO II detector operating at the CESR e⁺e^- collider. We present fits to phenomenological models in which resonance parameters associated with the ρ(770) and ρ(1450) mesons are determined. The π^-π⁰ spectral function inferred from the invariant mass spectrum is compared with data on e⁺e^-π⁺π^- as a test of the conserved vector current theorem. We also discuss the implications of our data with regard to estimates of the hadronic contribution to the muon anomalous magnetic moment. ©2000 The American Physical Society.