Complete set of πd observables and dibaryon resonances

Abstract

The formalism describing a complete set of observables for pi d elastic scattering is developed and explicit expressions for all spin observables including spin correlation parameters are given in the helicity formalism. The connection with standard partial waves is given. In the absence of a complete set of data the applications concentrate on the analysis of dibaryon resonances in the pi D channel. The vector polarisation it₁₁ is studied in detail. The dibaryon candidates ¹D₂,³F₃ and ¹G₄ are admixed to Faddeev background amplitudes. The effect of pion absorption is analysed using the results from the Lyon group as background. While the present data at 256 Mev are consistent with a strong ¹G₄ resonance coupled to L=5, the energy dependence of the oscillatory structure of it₁₁ ultimately will test individual resonance contributions. In the same model all the spin correlation parameters have been studied systematically. Sensitive probes of resonance properties are suggested.