Strangeness-exchange interactions at high energies

Abstract

In Chapter 1 we discuss the importance of a study of high energy strangeness-exchange reactions in elucidating the exchange mechanisms and symmetry properties of meson-baryon scattering. The cross-section and polarisation data for KN→πΣ, Δ and πKN→πΣ, Δ are reviewed in Chapter 2. An exchange-degenerate poles with weak cuts model for the data is proposed, and the resulting successful polarisation and unsuccessful cross-section descriptions are discussed. The model's failure to reproduce the well-known line reversal cross-section inequality at intermediate energies is interpreted in terms of low energy resonance effects. A unified treatment of non-zero exotic exchange processes and line reversal symmetry violation in terms of Regge-Regge cuts is presented in Chapter 3. After a theoretical appraisal of a multiple scattering approximation for these cuts we present explicit calculations of the exotic strangeness-exchange cross- sections for K(^-)p-π(^+)Σ(^-) and π(^-)p→K(^+)Σ(^-). It is shown that the small size of the data for these is not easily explained. Since we also show that the inclusion of non-leading cuts aggravates the disagreement between data and the leading cuts model, the usefulness of Regge-Regge cut descriptions at intermediate energies is called into question.