基于兰州重离子加速器实验装置物理目标的原子核多体系统理论研究

We plan to investigate the properties of asymmetric nuclear matter and finite nuclei related to the physics aims of HIRFL-CSR at Lanzhou, China. In the aspect of asymmetric nuclear matter, we shall improve and extend the microscopic nuclear many-body theories and the transport models for heavy-ion collisions. The density dependence of symmetry energy at high densities will be studied and its microscopic origin will be explored. Based on the predictions on the properties of nuclear matter within the microscopic many-body approaches, the nucleon-nucleon effective interactions in asymmetric nuclear medium will be improved, and new energy density functionals and/or new parameters will be proposed. In order to constrain the properties of asymmetric nuclear matter at high densities, various sensitive probes to symmetry energy in heavy-ion collisions will be studied systematically in the energy region of HIRFL-CSR. The uncertainties and model dependence of these sensitive probes for extracting the information of symmetry energy at high densities from heavy-ion collisions will be analyzed intensively. New sensitive probes to the high-density behaviour of symmetry energy will be explored and proposed. As for superheavy nuclei, we will investigate intensively the reaction mechanisms for synthesizing superheavy nuclei as well as the structure and decay properties of superheavy nuclei. New mechanisms for synthesizing superheavy nuclei and new approaches for predicting the properties of superheavy nuclei will be explored. In the study of the properties of nuclei far away from the nuclear stability line, new theoretical approaches and models will be developed. The effect of symmetry energy on the structure properties of heavy nuclei and nuclei far away from the nuclear stability line will be investigated systematically. Shell evolution and possible new shells will also be explored. Through the theoretical investigations of this project, we aim to provide useful information for the related experiments at HIRFL-CSR in the future.

开展与我国兰州重离子加速器实验装置（HIRFL-CSR）相关的非对称核物质与原子核性质方面的研究理论。在非对称核物质性质方面，改进和完善微观原子核多体理论方法和重离子碰撞输运理论模型，探索对称能高密度依赖行为的微观机制，基于微观多体理论预言结果扩展和改进非对称核物质中核子-核子有效相互作用。研究HIRFL-CSR能区各种对称能灵敏观测量，深入分析利用这些灵敏观测量提取对称能高密度行为时存在的不确定性，寻找新的灵敏探针和实验探测上可行的最佳关联观测量。在超重核方面，深入研究合成超重核的重离子反应机制以及超重核结构和衰变性质，探讨超重核合成的新途径。在弱束缚核结构方面，改进现有理论模型，发展适合于描述弱束缚滴线核结构性质的理论方法，研究对称能密度相关性对于重核以及远离稳定线核结构性质的影响，探索新的幻数位置。通过理论研究为将来HIRFL-CSR相关实验的开展提供理论参考。

原子核多体系统一直是核物理领域最具挑战性的重要研究内容之一。本项目主要开展与我国兰州重离子加速器实验装置相关的原子核多体系统理论研究，取得了一系列重要研究结果。从多个方面改进了重离子碰撞输运理论模型；率先研究并揭示了重离子碰撞中对称能灵敏观测量的模型依赖性；指出了重离子碰撞理论模拟中一系列不确定因素对于对称能灵敏观测量的重要影响；提出了定性探测对称能高密行为的模型无关灵敏观测量。基于微观多体理论提取了核物质中核子-核子相互作用的同位旋非守恒成分，推广了Wigner同位旋多重态质量方程，成功解释了二次方形式多重态质量方程的破缺、同位旋三重态和四重态实验结果以及Nolen-Schiffer反常问题。改进了原子核微观多体Brueckner理论计算；指出了张量力对于对称能密度依赖性的关键作用；揭示了质子-中子有效质量同位旋劈裂的微观机制；基于微观理论预言提出了核物质中质子-中子有效对力的参数化形式。指出了三体核力和连续态耦合效应对于描述A≈20区域丰质子核的必要性；通过多中子态理论研究发现三中子态比四中子态更容易被观测到并建议实验寻找三中子态。从多个方面研究了原子核多体系统中核子间短程关联效应，指出了中子-质子张量关联对核物质中核子动量分布的主导作用；揭示了非对称核物质中核子动量分布的标度性规律并基于微观理论预言给出了核子动量分布的参数化形式；提出了探测核子短程关联效应的灵敏探针；预言了核子短程关联对中子星中核子超流性的强烈抑制作用；澄清了核子短程关联导致的核子动量分布中高动量尾巴在中子星冷却中的作用。实现了中子星结构性质及其磁场分布的自洽计算；在中子星冷却理论研究中首次引入星体动力学演化与热演化的耦合效应，改进了传统的中子星冷却模型。建立了统一描述原子核结构和散射问题的非微扰时间依赖基函数方法并成功应用于d+208Pb垒下散射问题。本项目研究结果对于改进重离子碰撞输运理论模型、理解核子有效相互作用本质以及约束对称能高密行为有重要科学意义。