Georg Viehhauser

Abstract:

The CLEO experiment at the CESR collider has used 13.7 fb(-1) of data to search for the production of the Omega(0)(c) (css ground state) in e(+)e(-) collisions at square root of (s) approximately 10.6 GeV. The modes used to study the Omega(0)(c) are Omega(-)pi(+), Omega(-)pi(+)pi(0), Xi-K-pi(+)pi(+), Xi0K-pi(+), and Omega(-)pi(+)pi(+)pi(-). We observe a signal of 40.4+/-9.0(stat) events at a mass of 2694.6+/-2.6(stat)+/-1.9(syst) MeV/c(2), for all modes combined.

Abstract:

One year after the installation of most of the components of CLEO III, a strongly upgraded successor to the successful CLEO phase I and II experiments, and about half a year after its completion by the installation of the Silicon Detector, the experiment has successfully passed its commissioning phase and completed its first data-taking period. Major components of the detector upgrade are a new Drift Chamber with improved material distribution and a reduced volume to accommodate focussing accelerator components and the new particle identification system, a new four-layer Silicon Detector integrated in the overall tracking system to compensate for the reduced tracking volume and a proximity-focussing RICH with solid LiF crystal radiators and multi-wire proportional chambers filled with CH4/triethylamine. Preliminary performance benchmark studies have been completed and show that the CLEO III upgrade has been successful in achieving its design goals. (C) 2001 Published by Elsevier Science B.V.

Abstract:

We report results of a search for B-->tau(nu) in a sample of 9.7 x 10(6) charged B meson decays. We exclusively reconstruct the companion B decay to suppress background. We set an upper limit on the branching fraction B(B-->tau(nu))<8.4 x 10(-4) at 90% confidence level. We also establish B(B+/--->K+/-nu(nu))<2.4 x 10(-4) at 90% confidence level.

Abstract:

An analysis of 9.66 × 106 charged B meson decays which results in a conservative upper limit on the branching fraction B(B → τν) < 8.4 × 10-4. The analysis was slightly modified to establish B(B± → K± νν̄) < 2.4 × 10-4. The method used is optimized for conditions available at Y(4S) experiments, and some application of the method to other rare decay modes with large missing energy was aniticipated.

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. © 2001 Elsevier Science B.V.