相对论点耦合模型结合复动量表象方法研究^(74)Ca奇特结构

Exploration of the exotic structure of ^(74)Ca using the relativistic point-coupling model combined with complex momentum representation

本文介绍了奇特原子核的研究意义、研究方法及研究进展.给出了近期在相对论点耦合模型下结合复动量表象(CMR)方法和Bardeen-Cooper-Schrieffer(BCS)方法,发展的RMFPC-CMR-BCS方法的理论框架.本文重点是用此方法研究^(74)Ca的奇特结构.由于那些靠近连续谱阈值的单粒子态对奇特结构的形成有着重要作用,本文详细研究了对晕现象较为重要的单粒子态的波函数和密度分布,在用BCS方法考虑对关联作用后,低轨道角动量2d_(3/2)态因其是分布在最靠近连续谱阈值的共振态,最后一个核子将有很大概率弥散到2d_(3/2)共振态,从而使原子核半径增大,形成奇特晕现象.文中对这部分进行了详细研究,也展示出共振态对奇特结构形成的重要作用.

In this paper,the significance,methods,and progress of research on exotic nuclei are introduced.The theoretical framework of the RMFPC-CMR-BCS method developed by combining the complex momentum representation(CMR)and the Bardeen-Cooper-Schrieffer(BCS)methods according to the relativistic point-coupling model is given.This paper focuses on the investigations of the exotic structure of ^(74)Ca using the developed method.Because single-particle states near the continuous spectrum threshold are crucial to the formation of an exotic structure,the wave function and the density distribution of a single-particle state that are essential for the halo phenomenon are studied in detail.As the 2d_(3/2)state with low orbital angular momentum is closest to the continuum threshold,the last nucleon is likely to spread to the2d_(3/2)state after the BCS method is used to deal with the pairing correlation,which increases the radius of the nucleus.Details about the 2d_(3/2)state can be found,and it shows the relevance of resonance in the formation of exotic structures.