Analysis of (p, α) and (p,3He) cross-sections to continuum states by the Feshbach-Kerman-Koonin multistep direct theory

Abstract

Summary. -The cross-sections of several p; and p;3 He reactions at high energies to continuum states are analysed in order to obtain information on clustering in nuclei. -IntroductionThe presence of clusters of nucleons inside nuclei greatly enhances the cross-sections of cluster knockout and transfer reactions. It is therefore useful to study such reactions in order to determine the probabilities of various possible types of clusters.The most probable cluster in nuclei is the alpha-particle, due to its high symmetry and binding energy. Alpha-transfer and alpha knockout reactions have therefore been extensively studied in order to determine the alpha-clustering probability [1,2].One of the reactions most frequently used to study alpha-clustering in nuclei is the p; reaction, and many analyses of the differential cross-sections and analysing powers of this reaction to discrete states have been made [3] using either the triton pick-up or the alpha-particle knock-out models. Both models give rather similar results [5,4], but nuclear structure arguments favour the pick-up model. For a long time the calculations gave absolute magnitudes for the cross-section that were far too low [6,7] but detailed analyses [8] have largely removed the discrepancy, although some difficulties still remain [9].