Effective Field Theory for Few-Nucleons and Halo Nuclei

核物理学研究的一个中心目标是从量子色动力学（QCD）的基础理论中理解核的相互作用和性质。然而，在低能量下，QCD变成非线性和强相互作用，逃避了核性质的第一原理铅笔和纸计算。低能核物理学的一个重要方面是与弱束缚系统有关的物理。这些系统的一些特性在原子、核和粒子物理学中是普遍共有的。有效场论（EFT）公式允许系统地计算深深植根于量子动力学的核性质。EFT允许在计算中进行可靠的误差估计，否则在现象学方法中难以估计。在支持的研究工作中，将构建涉及电磁辐射的少体系统的EFT。将研究与大爆炸核合成和恒星燃烧有关的涉及轻核的关键反应。其中一些反应在解释粒子物理标准模型之外的实验结果方面起着重要作用。提出的工作还将引入新的模型无关的工具，具有可靠的误差估计来研究晕核。这些原子核被描述为紧密结合的核，通常由一个或两个价中子形成晕。这项研究与美国计划在稀有同位素束流实验方面的重大投资有关。该研究的更广泛影响包括培养物理研究生在数值和分析工作方面的学术或工业生涯，造福社会。这项研究工作的结果将被纳入研究生课程。由于上述的普适性，原子物理学的研究也会受到弱束缚少体系统研究的影响。具有大散射长度的原子系统形成了一个活跃的理论和实验研究领域。

A central goal in nuclear physics research is to understand nuclear interactions and properties from the underlying theory of Quantum Chromodynamics (QCD). At low energies, however, QCD becomes non-linear and strongly interacting, eluding first-principle pencil-and-paper calculations of nuclear properties. An important aspect of nuclear physics at low energy is the physics associated with weakly bound systems. Some properties of such systems are universally shared across atomic, nuclear and particle physics. The effective field theory (EFT) formulation allows for systematic calculations of nuclear properties that are deeply rooted in QCD. EFT allows reliable error estimates in calculations that are otherwise difficult to estimate in phenomenological approaches. In the supported research work, EFT for few-body systems involving electromagnetic radiation would be constructed. Key reactions involving light nuclei that are relevant in Big Bang Nucleosynthesis and stellar burning would be studied. Some of these reactions play an important role in interpreting experimental results probing physics beyond the Standard Model of particle physics. The proposed work would also introduce new model-independent tools with reliable error estimates to study halo nuclei. These nuclei are described as a tightly bound core with usually one or two valence neutrons forming a halo. This research ties in with planned major U.S. investment in rare isotope beam experiments.Broader impacts of the research include training of physics graduate students in numerical and analytical work for an academic or industry career benefiting society. Results from this research work would be incorporated in a graduate course. Atomic physics research would also be affected by this study of weakly bound few-body systems due to the universality described above. Atomic systems with large scattering lengths form an active field of theoretical and experimental research.