Georg Viehhauser

Abstract:

Using a sample of 4.7 fb-1 integrated luminosity accumulated with the CLEO-II detector at the Cornell Electron Storage Ring (CESR), we have measured the ratios of the branching fractions B(τ-→K-h+π-ν τ)/B(τ-→h-h+h -ντ)=(5.16±0.20±0.50) × 10-2, B(τ-→K-h+π-π 0ντ)/B(τ- →h-h+h-π0ν τ)=(2.54±0.44±0.39) × 10-2, B(τ-→K-K+π-ν τ)/B(τ-→h-h+h -ντ)=(1.52±0.14 ±0.29) × 10-2, and the upper limit B(τ-→K-K+π-π 0ντ)/B(τ-→h-h +h-π0ντ)<0.0154 at 95% C.L. Coupled with additional experimental information, we use our results to extract information on the structure of three-prong tau decays to charged kaons. ©1999 The American Physical Society.

Abstract:

Using a 4.19 fb -1 data sample collected with the CLEO II detector at the Cornell Electron Storage Ring, we have searched for dipion transitions between pairs of Y resonances at center of mass energies E c.m. = 10.58 GeV and E c.m. = 10.52GeV. We obtain the 90% confidence level upper limits B(Y(4S) →Y(2S)π + π - )<3.9×10 -4 and B(Y(4S)→Y(1S)π + π - )<1.2×10 -4 . We also observe the transitions Y(3S)→Y(1S)π + π - , Y(3S)→Y(2S)π + π - , and Y(2S)→Y(1S)π + π - , from which we measure the cross sections for the radiative processes e + e - →Y(3S)γ and e + e - →Y(2S)γ. We obtain σ ee→Y(3S)γ = (17.8±3.0±1.7) pb and σ ee→Y(2S)γ =(15.5±1.3±1.4) pb at E c.m. = 10.58 GeV, and σ ee→Y(3S)γ =(27.3±5.0±2.6) pb and σ ee→Y(2S)γ =(16.3±1.8±1.5) pb at E c.m. = 10.52 GeV, which we compare with theoretical predictions. ©1999 The American Physical Society.

Abstract:

The CLEO-III detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented. (C) 1999 Elsevier Science B.V. All rights reserved.