Generalization of the peripheral model with inclusion of rescattering for (α, 2α) reactions

A peripheral model is proposed for calculations of the quasielastic knockout (α, 2α) in which one includes explicitly the contributions to the reaction amplitude from the pole and triangle Feynman diagrams corresponding to rescattering in the final state. The peripheral character of the (α, 2α) reaction in the vicinity of the quasielastic peak is taken into account phenomenologically by suppressing the contribution to the reaction amplitude from the internal region of the target nucleus. The model proposed is applied to the description of the reaction 6Li(α, 2α)2H at α-particle energies E0 = 40--80 MeV. The differential cross sections calculated are in good agreement with the measured values. The importance of the inclusion of rescattering effects even in the peripheral region of the reaction amplitude is shown. The nuclear vertex constants for 6Li → α+d are extracted from the analysis of experimental data