arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1704.06334nucl-th
收藏

超重核fission势垒的理论不确定性评估

Assessing theoretical uncertainties in fission barriers of superheavy nuclei

S. E. Agbemava, A. V. Afanasjev, D. Ray, P. Ring

摘要:

本文系统地研究了超重元素内裂变势垒高度预测中的理论不确定性问题,给出了一组最新的协变能量密度泛函,这些泛函代表了协变密度泛函理论中的主要泛函类型。它们在基本模型假设和拟合协议方面有所不同。系统和统计的不确定性都被量化,其中前者更大。超重元素的系统不确定性是很大的,它们作为质子和中子数的函数的行为包含很大的随机分量。对锕系元素裂变势垒实验数据的泛函基准可以减少未知超重元素内部裂变势垒的系统理论不确定性。然而,即使这样,它们在离开进行基准测试的区域时平均也会增加。此外,与非相对论方法的结果进行比较,以定义完整的系统的理论不确定性的国家的最先进的模型。即使是以锕系元素为基准的模型,某些超重元素内部裂变势垒高度的差异也达到了$5-6$ MeV。裂变势垒高度的这种不确定性将转化为自发裂变半衰期的巨大(数十个数量级)不确定性。

英文摘要:

Theoretical uncertainties in the predictions of inner fission barrier heights in superheavy elements have been investigated in a systematic way for a set of state-of-the-art covariant energy density functionals which represent major classes of the functionals used in covariant density functional theory. They differ in basic model assumptions and fitting protocols. Both systematic and statistical uncertainties have been quantified where the former turn out to be larger. Systematic uncertainties are substantial in superheavy elements and their behavior as a function of proton and neutron numbers contains a large random component. The benchmarking of the functionals to the experimental data on fission barriers in the actinides allows to reduce the systematic theoretical uncertainties for the inner fission barriers of unknown superheavy elements. However, even then they on average increase on moving away from the region where benchmarking has been performed. In addition, a comparison with the results of non-relativistic approaches is performed in order to define full systematic theoretical uncertainties over the state-of-the-art models. Even for the models benchmarked in the actinides, the difference in the inner fission barrier height of some superheavy elements reaches $5-6$ MeV. This uncertainty in the fission barrier heights will translate into huge (many tens of the orders of magnitude) uncertainties in the spontaneous fission half-lives.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑