Cross-sections for neutral channels in K P interactions between 1470 and 1560 MeV C.M. energy

Abstract

The results presented in this thesis are from the preliminary data on a K P formation experiment. The experiment was carried out at the Rutherford Laboratory using the British National Hydrogen bubble chamber with a Track Sensitive Target (T.S.T.) to afford gamma-ray detection. The final states selected for the analysis are Λºπº, ϵºπº and Kºn at incident momenta between 200 and 500 MeV(_c). The T S T technique employed in this experiment is discussed in detail, in particular its limitations and how they should be handled are described. The cross-sections for Λº + neutrals, Λºπ(^+)π(^-) and Kºn channels are obtained in 20 MeV (_c) momentum intervals and the presence of the Λ (1520) is quite clear. The kaon flux is determined by using the observed tau-decays. The data is divided into 6 intervals of incident momentum between 250 and 500 MeV(_c) and fits are made to the distribution of missing mass squared to the A -hyperon, the production angular distribution and the polarisation of the A . These fits gave the Legendre expansion coefficients describing the angular distributions and the polarisations for the Λºπº and ϵºπº final states. The results are in good agreement with the previous data. Finally events fitted as Λºπº and ϵºπº hypotheses with one associated gamma-ray are chosen. Here the gamma-ray is used to resolve the Λº/ϵº ambiguity. The observed production angular distributions for these events are compared with the results from the fit above using Λº and ϵº events without gamma-rays. Also, the decay proton angular distribution of the fitted ϵºπº events is compared with the results from the fit. There is a good consistency between the two results and that of the previous data.