V. Fadeyev

Construction, pattern recognition and performance of the CLEO III LiF-TEA RICH detector

We briefly describe the construction and performance of the LiF-TEA RICH detector constructed for the CLEO III experiment.

Bounds on the CP Asymmetry in b {r_arrow} s{gamma} Decays

We have measured the CP asymmetry A(CP) identical with[gamma(b-->sgamma)-gammab-->sgamma)]/[gamma(b-->sgamma)+gamma(b-->sgamma)] to be A(CP) = (-0.079+/-0.108+/-0.022) (1.0+/-0.030), implying that, at 90% confidence level, A(CP) lies between -0.27 and +0.10. These limits rule out some extreme non-standard-model predictions, but are consistent with most, as well as with the standard model.

Performance of the CLEO III LiF-TEA ring imaging Cherenkov detector in a high-energy muon beam

Abstract The CLEO III Ring Imaging Cherenkov detector uses LiF radiators to generate Cherenkov photons which are then detected by proportional wire chambers using a mixture of CH 4 and TEA gases. The first two photon detector modules which were constructed, were taken to the Fermilab and tested in a beam dump that provided high-momentum muons. We report on results using both plane and “sawtooth”–shaped radiators. Specifically, we discuss the number of photoelectrons observed per ring and the angular resolution. The particle separation ability is shown to be sufficient for the physics of CLEO III.

The CLEO-III ring imaging Cherenkov detector

Abstract The CLEO detector has been upgraded to include a state of the art particle identification system, based on the Ring Imaging Cherenkov detector (RICH) technology, in order to take data at the upgraded CESR electron positron collider. The expected performance as well as the preliminary results are reviewed from an engineering run during the first few months of operation of the CLEO III detector.

Experimental study of aerogel Cherenkov detectors for particle identification

Abstract A feasibility study of using silica aerogel as a radiator in a threshold Cherenkov counter was done in preparation for an upgrade of the CLEO detector at CESR. The detector design requires separation of kaons from pions in the momentum range of 0.7–2.8 GeV/ c with statistical resolving power of 10 −4 and ability to operate the device in a 1.5 T magnetic field. This note summarizes the results of an R&D and simulation studies as well as a conceptual design that satisfies such requirements.

The ring imaging detector for CLEO III The CLEO III Ring Imaging Cherenkov detector

The CLEO detector is undergoing major improvements in conjunction with a high luminosity upgrade of the CESR e+e− collider. A novel element is a state of the art particle identification system, based on a proximity focused Ring Imaging Cherenkov detector. This detector will provide an excellent hadron identification at all the momenta relevant to the study of the decays of B mesons produced at the ϒ(4S) resonance. Some features unique to our design will be discussed together with some results achieved on individual components.

First Observation of the Decay B →J/ψϕK

We present the first observation of the decay B->J/psi phi K. Using 9.6 million B meson pairs collected with the CLEO detector, we have observed 10 fully reconstructed B->J/psi phi K candidates, whereas the estimated background is 0.5+/-0.2 events. We obtain a branching fraction of Br(B->J/psi phi K) = (8.8+3.5/-3.0(stat)+/-1.3(syst))*10^-5. This is the first observed

THE CLEO RICH DETECTOR

B

Test beam results from the CLEO III LiF-TEA RICH

meson decay requiring the creation of an additional s sbar quark pair.