Nuclear Clustering Effects in Colliding N=Z and N≠Z Nuclei

Abstract

Reactions between various N=Z and N≠Z s-d shell nuclei (¹⁶O+⁴⁰Ca, ¹⁶O+⁴⁴Ca, ²⁴Mg+²⁴Mg, ²⁸Si+²⁸Si, ²⁸Si+³⁰Si, ³⁰Si+³⁰Si and ³²S+³²S) have been carried out recently [1–3]. These experiments are made at bombarding energies of 1.5 to 2 times the Coulomb barrier where the experiments do not distinguish between inelastic and transfer reactions. At these energies, though the transfer process is presumably very weak, some data are still recorded [1,2]. These data clearly indicate an explicit preference for alpha-cluster transfer in reactions using N=Z, alpha-particle nuclei and that as neutrons are added to the N=Z, alpha particle target, projectile or to both the reaction partners, then the occurrence of resonance-like structure for alpha-particle transfer gets suppressed. In particular, whereas at 75 and 80.6 MeV, the ¹⁶O+⁴⁰Ca reactions show an explicit preference for alpha-particle transfer [1,2], the 80.6 MeV ¹⁶O+⁴⁴Ca reaction does not indicate any such preferred alpha resonance structure [2]. In a recent paper, one of the authors and collaborators [4] have shown that the preferred alpha-cluster transfer in the reaction of 75 MeV ¹⁶O on ⁴⁰Ca is a collective mass fragmentation process and in this contribution we show that the same dynamical fragmentation theory also gives the other result of the experiments.