K核深束缚态形变效应的理论研究

Strange nuclei have several new phenomena and properties which are non-existent in finite nuclei. Due to the strongly attractive K¯N interaction, the K¯ mesons can be deeply embedded in a nucleus, which leads to the possible existence of deeply bound kaonic atoms or kaonic nuclei. The research on kaonic nuclei plays an important role in understanding the structure of nuclear matter and obtaining the information of strong interaction between strange meson and nucleon. In recent years, with the development of experiment, kaonic nuclei becomes a hot topic in nuclear physics. The structure of kaonic nuclei is usually taken as spherical shape, while the deformation effect is not taken into consideration theoretically. And the effect of antikaon on the deformation properties of kaonic nuclei has not been studied yet. Based on the framework of relativistic mean field theory, the aim of this project is to develop the axially deformed calculation method to investigate the deformation effect of kaonic nuclei. The detailed research content of this project includes the following two parts: (1) Part of this project is devoted to investigate the effect of antikaon optical potential on the antikaon binding energy, the decay width, and the antikaon density distribution in kaonic nuclei, in order to obtain the underlying information on the K¯N interaction. (2) The second motivation of the present project is to extend the theoretical exploration of kaonic nuclei to an axially deformed calculation method on the relativistic mean field model. Meanwhile, the deformation effect of kaonic nuclei is also investigated by the combination of the constrained relativistic mean field method.

奇异性原子核具有许多不同于普通原子核的新现象和新性质。带奇异量子数的K-介子与核的吸引作用较强，原子核中可能存在K-介子束缚态，形成K核。K核物理研究对于理解物质的深层次结构，提取奇异介子与核子（YN）的强相互作用信息具有重要的作用。近年来，伴随着实验的发展，K核物理研究逐渐成为当前国际核物理研究的热点问题之一。在当前的理论研究中，K核通常被看成球形来处理，K核的形变效应并未加以考虑，而K-介子对K核核芯的形变效应，是需要解决的一个重要问题。本项目在相对论平均场理论框架下，发展K核的轴形变计算理论，研究K核束缚态的形变效应，具体的研究内容包括：（1）定量研究K-介子光学势对K核的结合能、衰变宽度以及K-介子在K核中密度分布等的影响，从而理论分析K核束缚态性质与KN相互作用的依赖关系。（2）在K核的相对论平均场轴形变理论基础上，进一步结合形变约束计算方法，研究K核束缚态形变结构特性。

本项目旨在推广的夸克质量密度依赖模型（IQMDD）框架下，研究lambda超核以及K介子核束缚态问题。.1，首先是发展夸克、介子耦合的相对论平均场理论，并用于lambda超核的理论研究。其次， 在原有K介子的复数形式Klein-Gordon方程的球形求解思路基础上，发展复数形式的Klein-Gordon方程的轴对称形变求解方法，利用轴对称谐振子势的本征函数展开法，迭代求解包含K介子运动方程在内的耦合方程组。这部分工作已经完成，正在系统计算分析数据并撰写论文。.2，最后，针对一些在基态下具有中心密度压低的气泡结构的原子核，以及具有形状共存的原子核内可能的K核束缚态，在形变情况下研究K介子对核子单粒子能级的影响，并通过对其位能曲面的计算来研究K核束缚态的结构形变。这部分工作正在开展。