Electroweak reactions on nuclei from first principles

从第一原理看原子核的电弱反应

• 批准号: SAPIN-2015-00031
• 负责人: Bacca, Sonia
• 金额: $ 2.77万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=614384
• 关键词: Electroweak; reactions; nuclei; first; principles

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.

原子核是位于每个原子中心的致密物体。它们由两种核子组成，质子和中子，它们相互作用。原子核驱动着化学元素的合成，它们可以作为星星的燃料，也可以作为实验室来测试基本对称性和标准模型。核理论的目标是为一些基本问题提供答案，例如：核力的性质是什么？质子和中子如何结合在一起形成稳定和不稳定的原子核？我们如何利用原子核来发现基本相互作用和粒子的性质？ 该提案旨在通过结合原子核理论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）新的从头算多体方法，以计算原子核上的电弱反应。 从我以前的经验，在轻核的电磁反应，我计划应用创新的理论工具，如洛伦兹积分变换和耦合集群理论，扩展从头计算的原子核在中等质量的制度，包括电磁和弱反应。 我计划解决磁性和伽莫夫-特勒反应在中子丰富的核，探索与ISAC实验计划的协同作用。此外，在核理论的帮助下，我计划为原子和粒子物理学做出贡献，解决涉及核物理的重要问题。 利用少体精确方法，我建议计算μ子原子的核结构修正，这是由原子物理学界进行实验，以解开所谓的“质子半径之谜”的奥秘所要求的。核结构效应是μ子原子实验中的主要不确定性，可以用核理论计算，并具有足够的精度。这是理解新的力是否在μ子原子中起作用的关键。最后，这个提议的一个长期目标是使用从头算耦合簇理论来解决中微子-核相互作用，重点是16 O。后者对于旨在测量中微子基本性质的粒子物理实验至关重要，例如T2 K，目前数据分析系统地受到核物理不确定性的限制。 这项发现补助金申请旨在利用与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作用，并与加拿大亚原子物理长期计划保持一致。这一提议的成功可能对核物理产生强大的科学影响，对原子和粒子物理界也有重要影响。它将大大加强加拿大在核理论方面的努力，并有助于下一代加拿大核物理学家的教育。