建立推广的宏观微观模型研究超重核衰变性质

The synthesis of superheavy nuclei achieved significant progress due to the rapid development of the accelerator technology and the radioactivity beams since 21 century. But whether the stability island of superheavy nuclei exists, in the other world, where the island located is still a open problem associated with the experimental data. The detected experimentally decay modes of superheavy nuclei are alpha decay and spontaneous fission. Recently, possibility of heavy particle radioactivity for superheavy nuclei is also predicted. So the study on decay dynamics of superheavy nuclei will not only provide guides on related experiments, but also be useful for improvement of the nuclear theoretical model. We will develop the present macro-microscopic model by introducing the quasi-molecular shape sequences and the proximity in the project. The new model named generalized macro-microscopic model, which can describe the alpha decay, heavy particle radioactivity and spontaneous fission. We will study systematically the decay properties in the framework of the generalized macro-microscopic model. Our work will focus on the competition of different decay modes, and prediction the location and range of the stability island of superheavy nuclei. We will also give some ground state properties of the nuclei in the stability island.

21世纪以来，得益于加速器技术及放射性束流物理的发展，超重核的实验合成取得了举世瞩目的成果。但对于超重核稳定岛的具体位置在哪里还无法从已有的实验结果得出定论。实验上发现超重核的衰变模式主要是阿尔法衰变和自发裂变，近年有理论预言超重核也可以发生重粒子放射性。对超重核衰变性质的理论研究，不仅可以为实验工作提供重要指导，而且通过理论与已有实验结果的比较，发展现有的原子核理论模型。本课题拟发展现有的宏观微观模型，引入准分子形状机制，考虑亲和力的贡献，使其发展为可以用来统一描述原子核阿尔法衰变、重粒子放射性及自发裂变等性质的新模型----推广的宏观微观模型。在此基础之上，系统研究超重核的衰变性质以及不同衰变模式之间的竞争机制，理论上确定超重核稳定岛的中心位置和岛屿的范围以及预言稳定岛上原子核的性质。

将准分子形状引入到宏观微观模型，从而研究原子核按照按照准分子形状所定义的过程进行演化时总能量包括微观壳修正能和对修正能的演化。在此演化过程（即描述超重核衰变过程）中，不但包括了微观壳修正和对关联等核结构信息，而且在衰变过程中可以形成深而窄的脖子及其演化过程，我们将新建立的模型成为推广的宏观微观模型。采用该模型，系统研究了原子核的阿尔法衰变（代表成果Phys. Rev. C 96, 024302 (2017)；Journal of Physics G 45 (2018) 075106；Phys. Rev. C 102, (2020) 044308；Phys. Rev. C 101, （2020） 034307）、重粒子放射性（代表成果Phys. Rev. C 96, 021601(R) (2017)；Phys. Rev. C 102, (2020) 034318）以及原子核的自发裂变（Phys. Rev. C 90, (2014) 054313；Phys. Rev. C 96, 024302 (2017)；Chin. Phys. C 43, (2019) 044105）。根据超重核的这几种衰变性质，特别是衰变能与半衰的系统性研究，确认超重核稳定岛的中心为114号原子核298Fl，其中子数为184. 通过建立推广的宏观微观模型并成功用于超重核衰变性质的研究，不仅发展了原子核理论模型，而且对将来超重核的合成与探测及稳定岛的确定提供了重要的依据。