超饱和密度对称能密度依赖行为的研究

核物质状态方程是描述核物质性质的基本方程，是联系核子-核子微观相互作用与中子星等核天体宏观性质的桥梁。表征其同位旋相关部分的对称能是核物理和天体物理研究的热点之一，超饱和密度对称能的密度依赖行为的研究对核物理和天体物理中许多关键问题的理解至关重要。本项目拟基于同位旋相关的Boltzmann-Uehling-Uhlenbeck(IBUU)输运模型，模拟在实验室中产生高密高非对称核物质的中高能重离子碰撞过程，通过对弹靶核的核子密度分布三维初始化以改进模型，计算多种丰中子反应系统，探索生成持续时间较长的高密核物质的弹靶组合；利用深度神经网络构建对称势到观测量的映射，开发探测对称能高密行为的敏感观测量。将输运模型模拟得到的结果与重离子核反应产生的π介子、κ介子、核子、轻碎片等相关实验数据进行比较，约束超饱和密度对称能的密度依赖行为。

The equation of state of nuclear matter is the basic equation to describe the properties of nuclear matter and a bridge between nucleon-nucleon microscopic interaction and macroscopic properties of celestial body such as neutron stars. The symmetry energy characterizing its isospin part is one of the hotspots in nuclear physics and astrophysics. Its density-dependent behavior at supersaturation density is crucial to the understanding of many key problems in nuclear physics and astrophysics. This project intends to base on the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, simulate the heavy ion collision process at intermediate high energy only which can produce high density asymmetric nuclear matter in terrestrial experiments, initialize the three-dimensional nucleon density distribution of the reaction system to develop the model, calculate the neutron-rich reaction systems to find some applicable bomb-target combinations producing high-density nuclear mater for a quite longer time, use deep neural network to construct the mapping from the symmetric potential to the observables, find some sensitive observations to probe symmetry energy high density behavior. The results obtained by the transport model simulation will be compared with the experimental data of pion meson, kaon meson, nucleon and light fragmentations produced by the heavy ion nuclear reaction, and constrain the density dependence behavior of symmetry energy at supersaturation density.