Ab initio nuclear theory for applications in astrophysics and tests of fundamental symmetries

从头算核理论在天体物理学和基本对称性测试中的应用

• 批准号: SAPIN-2022-00019
• 负责人: Navratil, Petr
• 金额: $ 8.01万
• 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: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=765952
• 关键词: Ab; initio; nuclear; theory; applications

Atomic nuclei are quantum many-body systems made by protons and neutrons interacting with forces that originate from the fundamental theory of Quantum Chromo-Dynamics. The exact treatment of nuclei starting from the constituent nucleons and the inter-nucleon interactions among them has been a long-standing goal in nuclear physics. The goal of this project is to develop a predictive ab initio theory of nuclear structure and nuclear reactions for light and medium mass nuclei. Such a theory is needed to understand nuclear reactions important for astrophysics, to calculate electroweak reactions and decays of nuclei, to provide nuclear physics input for tests fundamental symmetries and for search for physics beyond the standard model, to understand fusion reactions important for the future energy generation, and to interpret the structure of exotic nuclei investigated at facilities like ISAC/ARIEL at TRIUMF. At the same time, it provides a feedback on the quality of inter-nucleon interactions used as input to these calculations and ultimately helps to improve our knowledge of the nucleon-nucleon interaction, and in particular of the still-not-completely-understood three-nucleon interaction. In this proposal, we combine an ab initio nuclear structure approach capable to describe bound states of nuclei with a microscopic cluster method developed to describe reactions of nuclear clusters. The resulting method provides a unified description of both bound and unbound nuclear states starting from inter-nucleon interactions among protons and neutrons. We will apply this method for example to improve our understanding of reactions with 8Be as the composite system, e.g., the transfer 7Li(p,n)7Be and electromagnetic captures 7Li(p,?)8Be and 7Li(p,e+e--)8Be relevant for Big Bang nucleosynthesis and the 7Li puzzle as well as for the recently claimed observation of a 17 MeV fifth--force boson. We will investigate 10C?10B and 14O?14N beta decays relevant for probing of the CKM matrix unitarity, an important test of the standard model. We will also focus on the 6He?6Li transition including predictions of the ß--energy spectrum investigated experimentally at present, which is one of the precision tests looking for evidence of interactions beyond the standard model. As experiments are proposed to measure nuclear spin -dependent parity- violating effects in polyatomic molecules, we will continue our calculations of anapole moments of the involved nuclei and focus on contributions from different terms of parity -violating nucleon-nucleon interaction. A similar sensitivity study will be performed in calculations of nuclear electric dipole moments. Finally, a long-term goal of this project is the calculation of reactions important for stellar synthesis of 12C and 16O. This is now within reach as the a--a scattering capability has been developed. The complexity of theoretical understanding of these reactions requires exa-scale computing.

原子核是由质子和中子与源自量子色动力学基本理论的力相互作用形成的量子多体系统，从组成核子及其核子间相互作用开始对原子核进行精确处理已经有很长的历史了。 - 核物理学的长期目标是开发轻质和中等质量核的核结构和核反应的预测性从头理论。天体物理学，计算核的电弱反应和衰变，为测试基本对称性和寻找标准模型之外的物理提供核物理输入，了解对未来能源产生重要的聚变反应，并解释所研究的奇异核的结构在 TRUMF 的 ISAC/ARIEL 等设施中，它提供了有关核子间相互作用质量的反馈，用作这些计算的输入，最终有助于提高我们对核子间相互作用的了解。核子-核子相互作用，特别是尚未完全理解的三核子相互作用在本提案中，我们将能够描述核束缚态的从头算核结构方法与开发用于描述反应的微观簇方法相结合。由此产生的方法从质子和中子之间的核间相互作用开始提供对束缚和非束缚核态的统一描述，我们将应用这种方法来提高我们的理解。以 8Be 作为复合体系的反应，例如，转移 7Li(p,n)7Be 和电磁捕获 7Li(p,?)8Be 和 7Li(p,e+e--)8Be 与大爆炸核合成和 7Li 有关谜题以及最近声称的 17 MeV 第五力玻色子的观测 我们将研究 10C?10B 和14O?14N β 衰变与探测 CKM 矩阵幺正性相关，这是标准模型的一个重要测试。我们还将重点关注 6He?6Li 跃迁，包括目前实验研究的 ß 能谱的预测，这是其中之一。精密测试寻找超出标准模型的相互作用的证据，随着实验被提出来测量多原子分子中核自旋相关的宇称破坏效应，我们将继续计算所涉及的原子核和的阿纳极矩。重点关注不同宇称破坏核子-核子相互作用项的贡献，在核电偶极矩的计算中将进行类似的敏感性研究，该项目的长期目标是计算对恒星合成重要的反应。 12C 和 16O。随着 a--a 散射能力的发展，这一点现在已经可以实现。这些反应的理论理解非常复杂，需要亿级计算。