For the forward going ejectile, the $\Delta$ excitation and the coherent pion emission in the charge exchange reaction have been described by the real pion induced reaction. Using a pseudovector pion coupling to nucleon and the eikonally distorted waves for projectile and ejectile, the double differential cross section for the ejectile energy/momentum distribution is written in terms of the cross section for pion scattering on the nucleus. This cross section has been approximated by the corresponding measured cross section for the real pion. Calculated spectral shapes for various reactions agree very well with the measured distributions.

• Received 17 October 2001

DOI:https://doi.org/10.1103/PhysRevC.66.014604