重核和超重核衰变寿命的系统计算

Research on properties of heavy and superheavy nuclei is one of hot topics in current nuclear physics. Recently experimental researches have achieved new progresses, it is of great improtance to systematically investigate the properties of heavy and supeheavy nuclei from the theoretical standpoint. The objective of theoretical researches is not only to explain the available experimental data but also to predict the properties of superheavy nuclei that will be synthesized in experiments. At present, the identification of superheavy nuclei mainly resorts to the observation of alpha-decay chains.This project is to perform systematic calculations of decay properties of heavy and superheavy nuclei. First, we will use nuclear decay models devolped by our group to calculate the decay properties of unstable heavy and superheavy nuclei, including alpha-decay half-lives, alpha-decay fine structure, beta-decay half-lives, and fission half-lives. The calculated results are compared with the experimental data so as to discern the success and failure of the theoretical models. By analyzing the diffefences between theoretical results and experimental data, we will extract new physical factors and improve the theoretical models. Then, we will use the improved models to investigate the competition among various decay modes and analyze the key factors affecting the stability of superheavy nucei. Some possible new laws and new phenomenon would be explored in the superheavy mass region, which would be useful for future experimental researches. Our theoretical investigation on heavy and superheavy nuclei not only provides a good opportunity to test the available theoretical models and develop new models, but also is helpful for synthesis of superheavy nuclei at large experimental facilities in China.

超重新核素（新元素）性质的研究是当前国际核物理研究的热点之一。最近实验研究取得了一些新进展，因此对重核和超重核性质进行系统理论研究具有重要意义，不仅可解释新的实验结果，还能对实验上未知的超重新元素和新核素的性质给出预言。当前超重核主要通过观测阿尔法衰变链鉴别的，本项目将系统计算重核和超重核的衰变性质。首先用我们最近发展的核衰变模型计算不稳定核衰变性质（如alpha衰变寿命和精细结构现象、beta衰变寿命）和自发裂变寿命，比较理论计算结果和现有实验数据的差异，分析模型的成功之处和不足之处，提取新的物理因素，发展和完善现有核衰变模型。我们将用发展后的模型，研究各种衰变模式之间的竞争，分析影响超重核寿命的关键因素，寻找超重区域可能存在的新规律和新现象，为实验研究提供参考。这方面的理论研究，不仅可以检验现有理论模型并发展新的理论模型，还将有助于在国内的大科学装置上合成超重原子核。

超重新核素（新元素）性质的研究是当前国际核物理研究的热点之一。最近实验研究取得了一些新进展，因此对重核和超重核性质进行系统理论研究具有重要意义，不仅可解释新的实验结果，还能对实验上未知的超重新元素和新核素的性质给出预言。本项目研究重核和超重核的衰变过程。发展了对重核、超重核的一些重要衰变模式的理论计算方法，并进行了系统的研究与计算，理论与实验符合很好。特别针对alpha衰变模式，进行了更为深入的研究。对alpha衰变的预形成几率进行了计算；对密度依赖结团模型进行了拓展，将同位旋自由度、电子屏蔽效应、核介质效应引入了重核和超重核α衰变寿命计算之中。另外，利用不稳定核衰变实验数据，成功地提取了一些被广泛关注的重要物理参数：包括超重核和远离稳定线奇特核的半径、核物质对称能在饱和密度处的斜率、第四阶泰勒展开系数等。项目资助期间，正式发表论文70余篇,其中Phys. Lett. B 4篇，Phys. Rev. C 29篇，还培养了9名博士，主办了2个国际会议。