Georg Viehhauser

Abstract:

We have performed the first search for CP violation in tau lepton decay. CP violation in lepton decay does not occur in the minimal standard model but can occur in extensions such as the multi-Higgs doublet model. It appears as a characteristic difference between the τ− and τ+ decay angular distributions for the semileptonic decay modes such as τ− → K0 π− ν. We define an observable asymmetry to exploit this and find no evidence for any CP violation. © 1998 The American Physical Society.

Abstract:

We have measured the branching fractions for B → D®X, B → D®X, and B → D®Xℓ+v. From these results and some previously measured branching fractions, we obtain B(b → cc®s) = (21.9 ± 3.7)%, B(b → sg) < 6.8% at 90% C.L., and B(D0 → K− π+ = (3.69 ± 0.20)%. Implications for the “B semileptonic decay problem” (measured branching fraction being below theoretical expectations) are discussed. With the increase in the value of B(b → cc®s) due to B → DX, the discrepancy is no longer statistically compelling. © 1998 American Physical Society.

Abstract:

The CLEO II detector at the e+e− storage ring CESR has been used to search for two-photon production of the fJ(2220) decaying into π+π−. No evidence for a signal is found in 4.77fb−1 of data and a 95% C.L. upper limit on [τγγBπ+π−]fJ(2220) of 2.5 eV is set. If this result is combined with the BES Collaboration's measurement of fJ(2220)→π+π− in radiative J/Ψ decay and the recent CLEO result for [τγγBK0SK0S]fJ(2220), a 95% C.L. lower limit on the stickiness of 102 is obtained. This result for the stickiness provides further support for a substantial neutral parton content in the fJ(2220). © 1998 The American Physical Society.

Abstract:

We have studied semileptonic B meson decays with a p-wave charm meson in the final state using 3.29×106BB¯ events collected with the CLEO II detector at the Cornell Electron-Positron Storage Ring.We find a value for the exclusive semileptonic product branching fraction B(B−→D10ℓ−ν¯ℓ)B(D10→D*+π−) = (0.373±0.085±0.052±0.024)% and an upper limit for B(B−→D2*0ℓ-ν¯ℓ)B(D2*0→D*+π−)<0.16% (90% C.L.).Furthermore, we present the first measurement of the q2 spectrum for B−→D10ℓ−ν¯ℓ. © 1998 The American Physical Society.

Abstract:

Using a data sample with an integrated luminosity of 3.9 fb-1 collected in e+e- annihilation with the CLEO-II detector at the Cornell Electron Storage Ring, we have measured the branching ratios for the decay modes Ds+→(η,η′)π+ and Ds+→(η,η′)ρ+ relative to Ds+→φ+. These decay modes are among the most common hadronic decays of the Ds+ , and can be related by factorization to the semileptonic decays Ds+ →(η,η′)ℓ+νl. The results obtained are compared with previous CLEO results and with the branching ratios measured for the related semileptonic decays. We also report results on the Cabibbo-suppressed decays of the D+ to the same final states. © 1998 The American Physical Society.