基于Gamow壳模型对天体过程中部分关键核反应及相关弱束缚核结构性质的研究

Nuclear astrophysics is one of the frontiers and central issues of nuclear physics. In our country, the related experimental research gradually takes the international leading level. Especially, the establishment of JinPing Underground Laboratory for Nuclear Astrophysics, has brought us many opportunities. In this background, we plan to start the related theory work with nuclear astrophysics. Our project will be mainly focused on several key proton/neutron radiative capture reactions in the big bang nucleosynthesis and stellar evolution process, and also the structure property of weakly-bound nuclei which are involved in these reactions..Our main theoretical tools will be based on Gamow shell model and its reformulations in the coupled-channel representations. The advantage of this method lies in the reconciliation of the structure and reaction description in a unified framework, and also the exact treatment of the continuum effect. It is sufficient to describe the weakly-bound exotic nuclei and its corresponding reaction process. With the investigation of this project, the structure property of ground and excited states in weakly-bound exotic nuclei, especially the energy and width of resonance state, the low-energy capture cross sections, astrophysical S factor, the resonance behavior close to the proton or neutron emission threshold, and also the influence of continuum can be understood well, so that we could supply predictions and analysis to the experimental study of nuclear reactions, and provide references for other theory work.

核天体物理是核物理研究的前沿、热点之一，我国的相关实验研究也逐渐达到国际领先水平，尤其是锦屏山地下核天体物理实验室的设立，为我国核天体方向的发展提供了更多的机遇。在此大背景下，我们计划开展相关的核天体理论研究，主要是对于爆发性核合成和恒星演化过程中一些关键质子/中子辐射俘获反应及相关弱束缚核的结构性质进行研究。.我们的主要理论工具是基于Gamow壳模型及它在耦合道表象下的重建。该模型的优势在于实现了在统一的理论框架下对结构和反应的描述，并可以对连续谱效应进行严格处理，尤其适合描述弱束缚奇特核及其反应过程。通过本项目的研究，我们希望可以对弱束缚奇特核基态及激发态的结构性质，特别是共振态的能级及宽度，以及低能反应截面，核天体S因子，质子或中子发射阈值附近的共振态行为，以及连续谱效应等问题有更加深刻的认识，为相关的核反应实验提供预测和分析，为其他理论工作提供参考。

在本项目中，我们主要开展了弱束缚核的结构性质及中子/质子辐射俘获反应的研究。通过三年的实施，基本完成了预计的目标。我们完成了程序部分的拓展，实现了粒子空穴组态下的计算；研究了弱束缚核的能谱及电磁跃迁性质，探讨了连续谱对其结构性质的影响；并研究了两体相互作用，探讨了三体力在描述丰中子核结构性质方面的影响；通过调整原有的唯象相互作用的参数来包含多体效应，对丰中子Sn同位素的结构性质和相应的中子辐射俘获反应过程进行了计算研究，对更好地理解r过程意义重大。我们一共发表了13篇SCI论文，参加并协助组织了多项学术会议，拓展了国内外的学术合作，为今后开展更多弱束缚核物理问题研究打下了坚实基础。