Collaborative Research: Computational Faddeev approach to nuclear reactions

合作研究：核反应的计算 Faddeev 方法

• 批准号: 1520929
• 负责人: Filomena Maciel Nunes
• 金额: $ 15.01万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1520929&HistoricalAwards=false
• 关键词: Collaborative; Research; Computational; Faddeev; approach

Nuclear Science is tasked with answering questions such as: (i) How did matter come into being and how does it evolve? (ii) How does subatomic matter organize itself and what phenomena emerge? (iii) How can the knowledge and technology progress provided by nuclear physics best be used to benefit society? Providing answers to these questions depends on a detailed theoretical understanding of nuclear reactions, a field in which current approaches are either outdated or limited to a small number of applications. In this larger context, this project will focus on the theoretical study of deuteron-induced reactions. Due to the short lifetimes involving exotic nuclei, direct neutron capture measurements of relevance to the origin of the heavy elements are often not possible. Indirect techniques like deuteron induced reactions are a common tool to extract the relevant astrophysical rates. These reactions are part of ongoing experimental programs at radioactive beam facilities, as well as programs at future facilities such as the Facility for Rare Isotope Beams (FRIB). As such, this project will provide theoretical support to challenging experimental programs and will provide a unique training opportunity for graduate students and post-doctoral fellows.A reliable reaction theory is critical for the understanding the data produced at experimental programs using (d,p) reactions. From a theoretical perspective, (d,p) reactions are attractive because the scattering can be reduced to an effective three-body problem. One of the most challenging aspects of solving the three-body problems for nuclear reactions is posed by the repulsive Coulomb interaction. While for light nuclei the momentum-space Faddeev equations can be treated by screening the Coulomb force, a similar approach is difficult to implement for heavy systems. Indeed, for most of the new exotic nuclei to be produced at FRIB, currently available computational methods are not adequate. This project will address this critical need and provide an implementation of an exact Faddeev method for the three-body nuclear reaction problem, in which the Coulomb force will be treated without screening.

核科学的任务是回答这样的问题：（一）物质是如何产生的，它是如何进化的？(ii)亚原子物质是如何组织自己的，会出现什么现象？(iii)核物理学提供的知识和技术进步如何才能最好地用于造福社会？这些问题的答案取决于对核反应的详细理论理解，在这个领域，目前的方法要么已经过时，要么仅限于少数应用。在这个更大的背景下，这个项目将集中在氘核诱导反应的理论研究。由于涉及外来核的短寿命，与重元素起源相关的直接中子捕获测量通常是不可能的。间接技术，如氘诱导反应是一种常用的工具，以提取相关的天体物理率。这些反应是放射性束设施正在进行的实验计划的一部分，以及未来设施（如稀有同位素束设施（FRIB））的计划。因此，该项目将为具有挑战性的实验项目提供理论支持，并将为研究生和博士后研究员提供独特的培训机会。可靠的反应理论对于理解使用（d，p）反应的实验项目产生的数据至关重要。从理论的角度来看，（d，p）反应是有吸引力的，因为散射可以减少到一个有效的三体问题。解决核反应的三体问题最具挑战性的方面之一是由排斥库仑相互作用。虽然对于轻核，动量空间Faddeev方程可以通过屏蔽库仑力来处理，但对于重系统，类似的方法很难实现。事实上，对于大多数在FRIB产生的新的奇异核，目前可用的计算方法是不够的。该项目将满足这一关键需求，并提供一个精确的Faddeev方法的三体核反应问题，其中库仑力将被处理没有筛选的实施。