K.G. Baird

Performance of the CRID at SLD

Abstract This paper describes the performance of a large 4π Cherenkov Ring Imaging Detector (CRID) in the SLD experiment at the SLC at SLAC. We compare the most recent SLD results with those obtained during the R&D period, discuss various design features, and highlight some specific lessons derived from three years of operation.

The fluid systems for the SLD Cherenkov Ring Imaging Detector

The design and operation of the fluid delivery, monitor, and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID) are described. The systems deliver drift gas (C/sub 2/H/sub 6/+TMAE), radiator gas (C/sub 5/F/sub 12/+N/sub 2/), and radiator liquid (C/sub 6/F/sub 14/). Measured critical quantities such as electron lifetime in the drift gas and ultraviolet (UV) transparencies of the radiator fluids, together with the operational experience, are reported. >

Obtaining physics results from the SLD CRID

Abstract We describe the likelihood ratio method used for particle identification in the SLD CRID, which allows the use of the entire momentum range covered by the liquid and gas radiators, including the threshold regions. Its application to two preliminary physics analyses is also described.

Measurement of [alpha][sub [ital s]] from energy-energy correlations at the [ital Z][sup 0] resonance

We determine the strong coupling [alpha][sub [ital s]] from a comprehensive study of energy-energy correlations (EECs) and their asymmetry (AEECs) in hadronic decays of [ital Z][sup 0] bosons collected by the SLD experiment at SLAC. The data are compared with all four available predictions of QCD calculated up to [ital O]([alpha][sub [ital s]][sup 2]) in perturbation theory, and also with a resummed calculation matched to all four of these calculations. We find large discrepancies between [alpha][sub [ital s]] values extracted from the different [ital O]([alpha][sub [ital s]][sup 2]) calculations. We also find a large renormalization scale ambiguity in [alpha][sub [ital s]] determined from the EECs using the [ital O]([alpha][sub [ital s]][sup 2]) calculations; this ambiguity is reduced in the case of the AEECs and is very small when the matched calculations are used. Averaging over all calculations, and over the EEC and AEEC results, we obtain [alpha][sub [ital s]]([ital M][sub [ital Z]][sup 2])=0.124[sub [minus]0.004][sup +0.003] (expt.) [plus minus]0.009 (theory).

Operational status and performance of the SLD CRID

Abstract The operation and performance of the SLD CRID achieved during the recently completed 1994–1995 run of the SLC will be discussed. Stable operation of liquid (C6F14) and gas (85% C5F12 and 15% N2) radiators with good UV transparency has been achieved. Our expectations for the future SLD physics program will also be briefly discussed.

THE FIRST RESULTS FROM THE CRID DETECTOR AT SLD

We report first results from the initial physics run of the Cherenkov Ring Imaging Detector (CRID) in the SLD experiment at the SLC. We describe the experimental conditions, show liquid and gas rings, report the number of photoelectrons per ring, and comment on resolution.

Operational experience with the SLD CRID at the SLC

We highlight some problems encountered and lessons learned in obtaining stable operation of the SLD CRID for the past four years. During the 1994–1995 run of the SLC, we achieved stable operation of liquid (C6F14) and gas (85% C5F1215% N2) radiators with good UV transparency, and we regularly operate the TPCs with excellent drift lifetimes and good single photo-electron detection efficiency.

Results from the SLD barrel CRID detector

We report on operational experience with and experimental performance of the SLD barrel Cherenkov Ring Imaging Detector from the 1992 and 1993 physics runs. The liquid (C/sub 6/F/sub 14/) and gas (C/sub 5/F/sub 12/) 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. >

The endcap Cherenkov ring imaging detector at SLD

We present the Cherenkov ring imaging detector in the endcap regions of the SLD detector and report initial performance. The endcap CRID was completed and commissioned in 1993 and is fully operational for the 1994 run. First Cherenkov rings have been observed. The endcap CRID detectors and fluid systems are described and initial operational experience is discussed. >

Performance of the endcap Cherenkov ring imaging detector at SLD

We present the Cherenkov Ring Imaging Detector in the endcap regions of the SLD detector and report on initial performance during the 1993 and 1994 runs at the SLC. The endcap CRID was completed and commissioned in 1993 and is fully operational for the 1994 run. First Cherenkov rings have been observed. The endcap CRID detectors and fluid systems are described and initial operational experience is discussed.<<ETX>>