| The doubly differential cross sections for the 4He(pi +, pi-)4p reaction were calculated by using a sequential single charge exchange model and an intranuclear cascade code. Final state interactions between two the struck nucleons was included in both methods. At energies 240 and 270 MeV, the low energy peak can be understood if the contribution of pion production is included. The calculated cross sections are compared with the data of Kinney et al.; The effect of the inclusion of final state interactions on pion production from nuclei with incident pion beams was calculated. The effect of absorption, with inclusion of the geometric considerations, explains the enhancement at low invariant mass seen in recent data for invariant mass spectra with increasing atomic number in most cases. |
