Research in Low-Energy Nuclear Theory

强相互作用是质子和中子与原子核结合的原因。提高对这种情况如何发生的定量理解不仅对于美国实验设施的基础核研究至关重要，而且对于天体物理学的进展、中微子的性质实验以及能源和国土安全的应用都是至关重要的。该项目在一定程度上使原子核结构和反应的精确计算进入了一个新纪元。活动包括扩大用于评估理论不确定性和物理发现的统计方法的范围和能力，开发和测试研究较重原子核的新的系统方法，以及改进从实验中提取最少依赖模型假设的信息。本科生、研究生和博士后研究助理在开展这些活动时接受的培训直接有助于建立一支多样化的科学队伍。学生和博士后必须使用分析和数值计算的组合，这是为学术和工业研究做好准备的良好准备，这一点得到了该小组过去成员的强劲记录的验证。项目分为三大类：有效场论(EFT)不确定性量化的贝叶斯统计方法，有限密度核系统的EFT，以及与过程无关的量的计算/提取。贝叶斯方法将应用于核子间相互作用、少数和多体系统以及弱电探针。他们将解决EFT截断误差、参数估计、模型选择和模型混合。最近关于密度矩阵展开和相空间对多体计算的贡献的研究将为进一步开展有限密度功率计算工作和重新研究核密度泛函理论的电子理论奠定基础。最后，PI和他的合作者将建立在从重整化群的角度理解敲除反应的最新进展的基础上，这突显了这些相互作用中的规模和方案依赖性，并提出了如何最好地分析依赖因式分解假设的实验的问题。应用范围从光学势能到短程相关物理的替代疗法。这些项目都有助于对具有量化不确定性的原子核进行微观的、独立于模型的计算。它们将影响长期计划中概述的低能核物理的前沿问题，如远离稳定性的原子核物理的结构和反应，这与天体物理和未来的稀有同位素束设施(FRIB)相关。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。

The strong interaction is responsible for the binding of protons and neutrons into atomic nuclei. Improved quantitative understanding of how this happens is essential not only for fundamental nuclear research at US experimental facilities but for progress in astrophysics, for experiments on the nature of neutrinos, and for applications to energy and homeland security. This project enables in part a new era of precision calculations of nuclear structure and reactions. Activities include extending the range and capabilities of statistical methods for assessing theoretical uncertainties and for physics discovery, developing and testing a novel systematic approach to heavier nuclei, and improving the extraction of information from experiment that minimally depends on model assumptions. The training received by undergraduates, graduate students, and postdoctoral research associates in carrying out these activities contributes directly to the building of a diverse scientific workforce. The mix of analytical and numerical computation the students and postdocs must employ is excellent preparation for both academic and industrial research, which is validated by the strong track record of past members of the group. Projects are in three major categories: Bayesian statistical methods for effective field theory (EFT) uncertainty quantification, EFT for finite density nuclear systems, and calculation/extraction of process-independent quantities. The Bayesian methods will be applied to inter-nucleon interactions, few- and many-body systems, and electroweak probes. They will address EFT truncation errors, parameter estimation, model selection, and model mixing. Recent studies of the density matrix expansion and phase-space contributions to many-body calculations will be the basis for further work on finite-density power counting and a renewed study of EFT for nuclear density functional theory. Finally, The PI and his collaborators will build on recent progress in understanding knock-out reactions from a renormalization group perspective, which highlights scale and scheme dependence in these interactions and raises questions about how to best analyze experiments that rely on factorization assumptions. Applications range from optical potentials to alternative treatments of short-range-correlation physics. These projects all contribute to the goal of microscopic, model-independent calculations of nuclei with quantified uncertainties. They will impact forefront problems in low-energy nuclear physics as outlined in the Long Range Plan, such as structure and reactions for the physics of nuclei far from stability, which is relevant for astrophysics and to the future Facility for Rare Isotope Beams (FRIB).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.