THE FLUID SYSTEMS FOR THE SLD CHERENKOV RING IMAGING DETECTOR

We describe the design and operation of the fluid delivery, monitor and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID). The systems deliver drift gas (C2H6+TMAE), radiator gas (C5F12+N2) and radiator liquid (C6F14). MeasUred critical quantities such as electron lifetime in the drift gas and ultra-violet (UV) transparencies of the radiator fluids, together with the operational experience, are also reported

PERFORMANCE OF THE SLD BARREL CRID DURING THE 1992 PHYSICS DATA RUN

The SLD Barrel Cherenkov Ring Imaging Detector was fully operational in the 1992 physics data run. The electron drift velocity and magnetic field deflection of electron trajectories have been measured. Cherenkov rings have been observed from both the liquid and gas radiators. The number and the resolution of the angle of Cherenkov photons have been measured to be approximately equal to design specifications

RESULTS FROM THE SLD BARREL CRID DETECTOR

We report on operational experience with an experimental performance of the SLD barrel Cherenkov Ring Imaging Detector from the 1992 and 1993 physics runs. The liquid (C6F14) and gas (C5F12) radiator recirculation systems have performed well, and the drift gas supply system has operated successfully with TMAE for three years. Cherenkov rings have been observed from both the liquid and gas radiators. The number and angular resolution of Cherenkov photons have been measured, and found to be close to design specifications

Measurement of A(b) and A(c) from the left-right forward - backward asymmetry of leptons in hadronic events at the Z0 resonance

The parity-violating parameters Ab and Ac are directly measured by the SLD experiment at the SLAC Linear Collider in e+e- collisions with polarized electrons at the Z0 resonance. Leptons with distinctive total and transverse momenta are used to select and analyze Z0→bb̅ and Z0→cc̅ events. Ab and Ac are extracted by forming the left-right forward-backward asymmetry in electron beam polarization and quark polar angle. From our 1993 sample of 1.8 pb–1 of Z0 decay data with an average electron beam polarization of 63% we find Ab = 0.91±0.14 (stat) ± 0.07 (syst) and Ac = 0.37±0.23 (stat) ± 0.21 (syst)