Theory of Direct Interaction in Nucleon Inelastic Scattering

For the inelastic scattering of nucleons at low and intermediate energies an approximate method is proposed by which the direct interaction process is calculated. From the coupled equation for the radial wave functions in various channels a standing wave solutions is obtained by perturbation approximation. For the asymptotic form of the wave function in outgoing channel we choose a proper form in such a way that the higher order contribution in perturbation expansion become small. The generalized K-matrix is calculated from the first order solution and later the S-matrix is transformed from the K-matrix. This method can give the exact solution in some simple cases and also is expected to give a good approximation in general cases. By assuming the simple zero-range force between nucleon in the nucleus and the incident neutron the approximate method is applied to the inelastic scattering of neutrons by Mg24. The effect of the Pauli principle is also estimated. The same process is calculated by assuming the collective excitation and both results are compared.