Strange meson spectroscopy in Kω and KΦ at 11 GeV/c and Cherenkov ring imaging at SLD

Abstract

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 interactionsmore » 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.« less