Final State Hyperon-Nucleon Interaction in Kaon Photoproduction from the Deuteron.
The extraction of the hyperon-nucleon interaction from a final-state interaction process is investigated. The choice of the deuteron as a target effectively eliminates nuclear structure effects present in complex nuclei. Apart from the weak K^+N interaction, the final state exhibits a pure Lambda -n interaction, which is unique to this reaction and is not available by means of LambdaN scattering. By calculating the deuteron wave function in the framework of the Reid and Paris NN potentials, the uncertainty caused by the nucleonic wave function was determined. The size of off-shell effects was estimated by employing a completely relativistic wave function and testing several approximations. Diagrammatic techniques that included low-lying baryon and meson resonances were used to derive the photoproduction operator, which was applied to the deuteron in a spectator nucleon model. The coupling constants were obtained by a least squares fit to kaon photo- and electro-production data from the proton. Final state effects were incorporated via a distorted wave formalism. Uncertainties due to the nucleonic wave function and off-shell effects are found to be negligible, whereas the photoproduction operator shows considerable influence on the cross section. To achieve a satisfactory description of the final state interaction, partial waves up to l = 3 need to be included. Final state effects dominate the cross section near threshold and disappear rapidly as the energy increases. Comparison of various LambdaN potential models display variations of up to 10%.
- Pub Date:
- December 1988
- Physics: Nuclear