Low-energy pion-deuteron scattering in a K-matrix model

Low-energy pion-deuteron scattering is studied in a K-matrix multiple scattering model. A comparison with predictions of the conventional T-matrix impulse approximation shows the real parts of the phase shifts to be practically identical but the imaginary parts to be substantially different. Thus, in applications where conservation of unitarity is essential the K-matrix approach should be preferred. (author)