The Influence Of Cluster Structure In ¹²C On Breakup Reaction Mechanism

Nuclear cluster structure exists in many light nuclei of ground and excited states.Experimental studies on cluster structure of many neutron rich isotopes,such as He?Li?Be?B?C?O,have been carried out by means of breakup reaction,transfer reaction,knock-out reaction,elastic scattering and inelastic scattering.Many theoretical calculations and experimental studies agree that there are?cluster structures in ¹²C nuclei.The study of the?cluster properties of Hoyle states and their nearby excited states in ¹²C is of great significance for star nuclear synthesis,nuclear structure,nuclear force and the origin of organic life.The energy level distribution and geometry of 3?clusters in¹²C nuclei are still controversial by different theoretical models and experimental studies.Breakup reaction is an important experimental method to study the structure of nucleon group in light nucleus excited state.However,the mechanism of Breakup reaction and the influence of nuclear cluster structure on this mechanism have not been fully studied.This paper mainly uses the antisymmetric molecular dynamics model,in which two kinds of calculations are used——fermi motion in the process of non-addition(AMD)and addition(AMD-DDFM)nucleon-nucleon collision.Theoretically,the fragmentation process of the ¹⁴N+¹²C reaction in the Fermi energy region is calculated.By analyzing the information of light particle physics(such as momentum,multiplicity of fragment,collision parameter distribution,etc.)generated at different times during the collision process,the effect of atomic nuclear cluster structure on the breakup reaction mechanism is studied.The results of this paper show that the AMD is closer to the experimental results than AMD-DDFM in the comparison of multiplicity.When analyzing the momentum distribution of light particles and the multiple distribution of fragment between projectile and target during collision and evaporation,it is found that ¹²C of fragmentation produce more?fragments than ¹⁴N of fragmentation.The?source of ¹²C fragmentation is that the ¹²C excited state decay of 7-15 Me V is 3?,among which,the famous¹²C Hoyle state contribution is obvious.