原子核内核子动量分布及短程关联现象的研究

With improvements of experimental conditions in recent years, the investigation of the short-range correlation (SRC) effects has been one of the frontier issues in nuclear physics. The research on the SRC phenomenon challenges the traditional shell model as well as the mean field approximation besides of its important implications to research on symmetry energy and tensor force, some important astrophysical processes, heavy-ion collisions, etc. Based on a combination of the microscopic Extended Brueckner-Hartree-Fock (BHF) many body approach and the local density approximation (LDA), the present project plans to calculate nucleon momentum distributions of nuclei, which will be applied to explore the SRC effects in finite nuclei. On top of that, the project is studying the following several issues. (1) The effect of the SRC on nucleon momentum distribution in nuclei and the roles played by tensor force and three-body force will be investigated in the project. (2) The project plans to explore systematically the validity of the so-called Tan relationship in medium- and heavy-nuclei as well as its physical interpretations. (3) The effect of the SRC on proton and neutron average kinetic energies, which is much concerned by both experiment and theory, will be studied and valuable information for related experimental research is expected to be obtained by the project.

近年来，随着实验条件的不断进步，短程关联效应的研究已经逐渐成为核物理的热点前沿问题之一。短程关联现象的研究为传统的壳模型和平均场近似提出了新的挑战，同时也对对称能和张量力的研究、一些重要的天体物理过程及重离子碰撞等问题有重要启发。本项目拟基于微观扩展的Brueckner-Hartree-Fock（BHF）多体理论结合局域密度近似计算原子核内核子的动量分布，并进一步利用该物理量研究有限核内的短程关联效应。主要研究内容包括：（1）考察短程关联对原子核内核子动量分布的影响，并研究张量力和三体核力在其中所起的作用；（2）系统地研究中重核中所谓Tan关系是否成立，并研究其物理本质；（3）研究目前实验和理论都非常关心的短程关联对原子核内质子和中子平均动能的影响，为今后相关的实验研究提供有价值的理论参考。

近年来，由于核子-核子短程关联相关问题在理解核力的短程性质等方面所拥有的独特优势而逐渐成为核物理新的前沿热点问题之一。短程关联效应的研究对检验核物理的壳模型、理解张量力、约束对称能高密行为以及研究一些重要的天体物理现象和重离子碰撞过程有重要意义。迄今为止，人们在实验和理论方面都已对核子-核子短程关联现象开展了大量的探索和研究。因此，本项目从微观多体理论出发，研究核物质和原子核内的短程关联现象。我们从微观扩展的Brueckner-Hartree-Fock（BHF）理论出发，利用局域密度近似方法计算了原子核内核子的谱函数，并与相应的实验数据做了比较，指出原子核内质子谱函数随原子核质量数的变化主要依赖于高密度区域质子所占的比重；利用扩展BHF方法计算了核物质中核子的动量分布，得到了简单的参数化公式描述核子的动量分布，正在进一步应用到计算原子核核子动量分布。此外，作为拓展内容，本项目也研究了质子-中子对关联及原子核反应理论等重要物理问题。相关研究对理解原子核短程关联实验数据具有重要意义，也为重离子输运理论和中子星冷却等课题提供了重要的输入量。