Contributions of quasifree and nonquasifree reaction processes to ($\pi$,$\pi \mathrm{N}$) reactions have been investigated across the (3,3) resonance region. We demonstrate that the quantum mechanical interference between these two types of reaction processes significantly affects the calculated ${\pi }^{-}$- and ${\pi }^{+}$- induced cross sections, as well as their ratio. In the case of incident ${\pi }^{-}$, the contributions from the interference term even exceed those from the pure nonquasifree term. This investigation of the ($\pi$,$\pi \mathrm{N}$) reaction thus indicates that the interpretations given to the parameter introduced into various published semiclassical models, in which interference effects were ignored, are incorrect.

• Received 8 February 1984

DOI:https://doi.org/10.1103/PhysRevC.30.254