Production of Σ(1660) in 4.2 GeV/c K-p collisions

In this thesis, an analysis of the production and decay of Σ+(1660) in K-p interactions at 4.2 GeV/c incident momentum is described. The production of Σ+(1660) for the channels Σ+π-π+π-, Σ-π+π+π-, Σ0π+π-, Λπ+π-, pantiK0π- and Λπ+π0π- is examined. The mass and width for the decay modes Σ+(1660)→Λ(1405) π+→Σ+π-π+ and Σ-π+π+ have been determined from fits to the effective mass distributions. The resonance parameters in the decay modes Σ+(1660)→ Σ0π+ and Σ+π0 are also determined. For the remaining channels, only upper limits for the production of Σ*(1660) can be determined. There is no observed production of Σ+(1660) in the channel K-p→ pantiK0π-. The production angular distribution shows a very significant difference between the distributions of Σ+(1660)→Λ(1405)π+ and of Σ+(1660)→(Σπ)+. This leads to the conclusion that (at least) two Σ(1660) resonances are being produced. Using the number of resonance events in both the Σ+π-π+ and Σ-π+π+ mode, the cross section for the reaction K-p→Σ+ with Σ+(1660)→Λ(1405)π+ is measured to be (23 +- 4)μb. The reaction cross section for the decay mode Σ+(1660)→(Σm)+ amounts to (33 +- 5)μb. The spin-parity analyses of the Σ(1660) are described. A significantly non-zero L=2 moment, for both the Λ(1405)π+ (→Σ+π-π+) and Σ0π+ decay modes is found thus estab lishing that in both cases the spin is J>=3/2. An Adair analysis and Byers-Fenster analysis of the different decays leads to a preference for J=3/2. An analysis of the Dalitz plot for the decay Σ+(1660)→Σ-π+π+ yields negative parity as the most probable hypothesis. The branching ratios for Σ(1660) are also determined