Collaborative Research: Computational Faddeev approach to Nuclear Reactions

核科学的任务是回答以下问题：(i)物质是如何产生的以及它是如何演变的？（ii）亚原子物质是如何自我组织的，会出现什么现象？如何才能最好地利用核物理学提供的知识和技术进步造福社会？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，目前的方法要么过时，要么仅限于少数应用。在这个大背景下，本项目将侧重于氘核诱导反应的理论研究。由于涉及外来核的寿命短，与重元素起源相关的直接中子捕获测量通常是不可能的。像氘核诱导反应这样的间接技术是提取相关天体物理速率的常用工具。这些反应是放射性束流设施正在进行的实验项目的一部分，也是稀有同位素束流设施（FRIB）等未来设施的项目的一部分。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提供独特的培训机会。一个可靠的反应理论对于理解在使用（d,p）反应的实验程序中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，因为散射可以简化为有效的三体问题。解决核反应的三体问题中最具挑战性的一个方面是由排斥性库仑相互作用提出的。对于轻核，动量-空间Faddeev方程可以通过屏蔽库仑力来处理，而对于重核系统，类似的方法很难实现。事实上，对于在FRIB产生的大多数新的奇异核，目前可用的计算方法是不够的。该项目将解决这一关键需求，并为三体核反应问题提供一种精确的Faddeev方法的实现，其中库仑力将不经过筛选处理。

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depends on a detailed theoretical understanding of nuclear reactions, a field in which current approaches are either outdated or limited to a small number of applications.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.