Strange meson spectroscopy in K(omega) and K(phi) at 11 GeV/c and Cherenkov ring imaging at SLD.

摘要

This thesis consists of two independent parts; development of Cherenkov Ring Imaging Detector (CRID) system and analysis of high-statistics data of strange meson reactions from the LASS spectrometer. Part 1: The CRID system is devoted to charged particle identification in the SLAC Large Detector (SLD) to study e(sup +)e(sup (minus)) collisions at (radical)s = m(sub Z(sup 0)). By measuring the angles of emission of the Cherenkov photons inside liquid and gaseous radiators, (pi)/K/p separation will be achieved up to (approximately)30 GeV/c. The signals from CRID are read in three coordinates, one of which is measured by charge-division technique. To obtain a (approximately)1% spatial resolution in the charge-division, low-noise CRID preamplifier prototypes were developed and tested resulting in <1000 electrons noise for an average photoelectron signal with 2 (times) 10(sup 5) gain. To help ensure the long-term stability of CRID operation at high efficiency, a comprehensive monitoring and control system was developed. Part 2: Results from the partial wave analysis of strange meson final states in the reactions K(sup (minus))p (yields) K(sup (minus))(omega)p and K(sup (minus))p (yields) (bar K)(sup 0)(phi)n are presented. The analyses are based on data from a 4.1 event/nb exposure of the LASS spectrometer in K(sup (minus))p interactions at 11 GeV/c. The data sample of K(sup (minus))(omega)p final state contains (approximately)10(sup 5) events. From the partial wave analysis, resonance structures of J(sup P) = 2(sup (minus)), 3(sup (minus)) and 2(sup +) amplitudes are observed in the K(omega) system. The analysis of 2(sup (minus)) amplitudes provides an evidence for two strange meson states in the mass region around 1.75 GeV/c(sup 2). The appropriate branching fractions are calculated and compared with the SU(3) predictions. The partial wave analysis of (bar K)(sup 0)(phi) system favors J(sup P) = 1(sup (minus)) and 2(sup +) states in the 1.9--2.0 GeV/c(sup 2) region.