Electroweak reactions on nuclei from first principles

原子核是位于每个原子中心的致密物体。它们由质子和中子这两种相互作用的核子组成。原子核驱动化学元素的合成，它们充当恒星燃料，可以作为测试基本对称性和标准模型的实验室。核理论的目标是为诸如：核力量的性质是什么等根本问题提供答案？质子和中子是如何结合在一起形成稳定和不稳定的原子核的？我们如何利用原子核来发现基本相互作用和粒子的性质？这个提议旨在通过结合原子核理论中的两个主要进展来解决这些问题：(I)有效场论的现代方法和(Ii)新的从头计算多体方法，以计算原子核上的电弱反应。 根据我以前对轻核电磁反应的经验，我计划应用创新的理论工具，如洛伦兹积分变换和耦合团簇理论，将从头计算扩展到中等质量区域的原子核，包括电磁反应和弱反应。我计划解决富中子核中的磁反应和伽莫夫-泰勒反应，探索与ISAC实验计划的协同效应。此外，在原子核理论的帮助下，我计划对原子和粒子物理学做出贡献，解决涉及原子核物理的重要问题。通过使用少体精确方法，我建议计算缪子原子的核结构修正，这是原子物理界在进行实验以揭开所谓“质子半径之谜”的奥秘时所呼吁的。核结构效应是缪子原子实验中的主要不确定因素，可以根据核理论以足够的精度进行计算。这是理解缪子原子中是否存在新的作用力的关键。最后，这项提议的长期目标是使用从头算耦合团簇理论来处理中微子-原子核相互作用，重点是16O。后者对于旨在测量中微子基本性质的粒子物理实验是至关重要的，例如T2K，目前数据分析受到核物理不确定性的系统性限制。 这项发现拨款申请旨在利用与TRIUMF的稀有同位素和粒子物理计划以及国外其他实验计划的协同效应，并与加拿大亚原子物理长期计划保持良好的一致性。这一提议的成功可能会对核物理学产生强大的科学影响，在原子和粒子物理界也会产生重要影响。它将大大加强加拿大在核理论方面的努力，并为加拿大下一代核物理学者的教育做出贡献。

Atomic nuclei are dense objects found in the centre of every atom. They are composed of two kinds of nucleons, proton and neutrons, which interact with each other. Nuclei drive the synthesis of the chemical elements, they serve as star fuel and can be used as laboratories to test fundamental symmetries and the Standard Model. The goal of nuclear theory is to provide answers to fundamental questions such as: What is the nature of nuclear forces? How do protons and neutrons tie together to form stable and unstable nuclei? How can we use nuclei to discover properties of fundamental interactions and particles? This proposal aims at tackling these questions by combining two major advances in the theory of nuclei: (i) the modern approach of effective field theory and (ii) novel ab-initio many-body methods, in order to calculate electroweak reactions on nuclei.  Drawing from my previous experience on electromagnetic reactions on light nuclei, I plan to apply innovative theoretical tools, such as the Lorentz integral transform and coupled-cluster theory, to extend ab-initio calculations to nuclei in the medium-mass regime, encompassing both electromagnetic and weak reactions.  I plan to address magnetic and Gamow-Teller responses in neutron-rich nuclei, exploring synergies with the ISAC experimental program. Moreover, with the help of nuclear theory, I plan to contribute to atomic and particle physics addressing important questions that involve the physics of nuclei.  Using few-body exact methods, I propose to calculate nuclear structure corrections in muonic atoms, which are called for by the atomic physics community performing experiments to unravel the mysteries of the so called "proton radius puzzle". Nuclear structure effects are the dominant uncertainties in muonic atoms experiments and can be calculated from nuclear theories with sufficient accuracy. This is key to understand if new forces are at play in muonic atoms. Finally, a long term goal of this proposal is to use the ab-initio coupled-cluster theory to address neutrino-nucleus interactions, with a focus on 16O. The latter are crucial to particle physics experiments aimed at measuring fundamental properties of neutrinos, such as T2K, where presently the data analysis is systematically limited by nuclear physics uncertainties. This Discovery Grant application aims at exploiting synergies with the rare isotope and the particle physics programs at TRIUMF as well as with other experimental programs abroad, and is well aligned with the Canadian Subatomic Physics Long Range Plan. The success of this proposal has potentially a strong scientific impact in nuclear physics,  with important implications also in the atomic and particle physics community. It will considerably strengthen the Canadian efforts in nuclear theory and contribute to the education of the next generation of Canadian nuclear physicists.