Direct Nuclear Reactions: Theory and Uncertainties

直接核反应提供了核物理学中一些用途最广的探测器，并提供了获得各种核性质的途径，其中大多数与天体物理和社会应用有关。具有已知不确定性的可靠反应理论是解释核反应实验的关键。这个项目旨在促进我们对一些不同反应数据中所包含的信息的理解。通过量化不确定性和评估用于解释给定实验的反应理论的置信度，该项目将使美国和世界各地现有和未来的稀有同位素设施得到更好的利用。具体地说，PI和她的学生将与实验者一起计划和解释在国家超导回旋实验室和密歇根州立大学未来的稀有同位素束设施正在进行的核反应实验。这个项目旨在促进我们对直接核反应的信息含量和不确定因素的理解，量化不确定度并评估从实验解释中提取的量的置信度。将开发工具来使用贝叶斯统计从数据中提取对光学势的约束，以及定义反应观察量的置信度范围。还将探讨减少该理论不确定性的策略。在从头算多体理论的指导下，贝叶斯工具将被应用于提取大范围质量和能量的非局部全局光学势。贝叶斯因子将用于进行模型比较，并确定反应模型中描述可用数据所需的复杂程度。PI和她的学生将专注于推进直接反应理论，特别关注不确定性量化。该项目的第二个目标是为多体方法和少体方法之间的直接联系铺平道路，并使人们能够更好地理解激发在直接反应过程中的作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Direct nuclear reactions provide some of the most versatile probes in nuclear physics and provide access to a large variety of nuclear properties, most of which are relevant for astrophysics and societal applications. Reliable reaction theory with known uncertainties is key for the interpretation of nuclear reaction experiments. This project aims to advance our understanding of the information contained in a number of different reaction data. By quantifying uncertainties and evaluating the level of confidence of the reaction theory used to interpret a given experiment, this project will enable a better use of current and future rare isotope facilities in the U.S. and worldwide. Specifically, the PI and her student will work with experimentalists in planning and interpreting on-going nuclear reaction experiments at the National Superconducting Cyclotron Laboratory and at the future Facility for Rare Isotope Beams at Michigan State University.This project seeks to advance our understanding of the information content and uncertainties concerning direct nuclear reactions, quantifying uncertainties and evaluating the level of confidence of the quantities extracted from the interpretation of experiments. Tools will be developed to use Bayesian statistics to extract constraints on the optical potential from data, as well as defining confidence bands for reaction observables. Strategies for reducing the uncertainty of the theory will also be explored. The Bayesian tools will be applied to extracting a non-local global optical potential for a wide range of masses and energies, informed by ab-initio many-body theories. The Bayes factor will be used to perform model comparisons and establish the level of sophistication needed in a reaction model to describe available data. The PI and her student will focus on advancing the theory for direct reactions with a particular focus on uncertainty quantification. A second goal of this project is to pave the way for a direct connection between many-body and few-body approaches and enable a better understanding of the role of excitation in direct reaction processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.