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中子与中子相互作用的量子多体系统，这些力与源自量子铬动力学的基本理论相互作用。核从结构核和核之间的相互作用开始的确切处理是核物理学的长期目标。该项目的目的是为轻质和中质核开发一种核结构和核反应的预测性。需要这种理论来理解对于天体物理学，计算电子反应和核的衰减至关重要的核反应，为测试提供基本对称性的核物理学输入，以及在标准模型以外的物理中搜索物理，以了解对未来能量产生重要的融合反应，并解释诸如ISAC/ARIEL诸如Triumf at Triumf的设施的结构。同时，它提供了用作这些计算输入的核之间相互作用的质量的反馈，最终有助于提高我们对核核子相互作用的了解，尤其是仍然没有完全完全理解的三核互动。在此提案中，我们将一种能够描述核定状态的核结构方法与开发的微观聚类方法相结合，以描述核簇的反应。最终的方法提供了从质子和中子之间的核之间相互作用开始的结合和未结合核状态的统一描述。例如，我们将使用这种方法来提高对与8BE作为复合系统的反应的理解，例如，转移7li（p，n）7be和电磁捕获7li（p，？）8be和7li（p，e+e-）8BE（p，e+e-）8BE与大爆炸核合成和7li puzzles and 7li spection-yspects of the 7li puzzle and a Moss obs obs obs obs obs ob a。我们将研究10c？10b和14o？14Nβ衰减与探测CKM矩阵单位相关的衰减，这是对标准模型的重要测试。我们还将重点关注6HE？6LI的过渡，包括目前对实验进行了研究的β-能量频谱的预测，这是寻找标准模型以外相互作用的证据的精确测试之一。由于提出了实验来衡量核自旋依赖性的平等性 - 违反多原子分子的影响，我们将继续计算所涉及的核的Anapole矩，并专注于不同奇偶校验的贡献 - 侵略性核核子相互作用。在计算核电偶极矩时，将进行类似的灵敏度研究。最后，该项目的长期目标是计算对12C和16O的恒星合成重要的反应的计算。由于已经开发了A - 散射能力，因此现在可以触及。对这些反应的理论理解的复杂性需要EXA级计算。