Inelastic effects in high-energy pion-deuteron scattering are investigated using a model in which the pion is a two-particle composite system. The inelastic pion form factors required in calculating inelastic pion-nucleon scattering are related to the elastic form factor by assuming that the low-lying states of the pion system are identical with the corresponding states of a nonrelativistic isotropic harmonic oscillator. In the model, pion-deuteron scattering can be viewed in two ways which are shown to be completely equivalent: as the scattering of two two-particle composites, or as pion-deuteron scattering in which excited pions can occur in intermediate states. Inelastic contributions are found to be negligible near the forward direction, but important at large angles. Including corrections from the lowest-lying excited states of the pion considerably improves the accuracy of the calculations at intermediate angles.

• Received 2 October 1969

DOI:https://doi.org/10.1103/PhysRevD.1.260