First-Principle Nuclear Structure and Reactions for Astrophysics and Experiments with Rare Isotope Beams

天体物理学和稀有同位素束实验的第一原理核结构和反应

• 批准号: 2209060
• 负责人: Kristina Launey
• 金额: $ 30万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2209060&HistoricalAwards=false
• 关键词: First; Principle; Nuclear; Structure; Reactions

Following the history-making discovery of nuclear fission, which manifested the huge amount of energy that is released by breaking the strong bonds between neutrons and protons, nuclear physicists have searched for ever more comprehensive explanations of the properties of the atomic nucleus. Such advances are critical to predict exotic nuclei in processes under extreme conditions as stellar mergers and explosions, and to probe neutrino-related processes. The recent advent of radioactive beam facilities has enabled exotic-nuclei measurements, based on collisions of nuclei and their reactions. To predict inaccessible nuclei, these reactions must be well understood and modeled. However, exact solutions exist up to about five particles. The objective of this program is to expand dramatically the capabilities of nuclear reaction theory, by providing input to reaction simulations that is anchored in first principles but also can accommodate heavier nuclei and enhanced deformation. This is important for studies of the origin of elements, one of the biggest challenges in physics today, and has a wider impact since nuclear energy applications and national security research have similar needs. Future leaders (postdoc and students) are trained in low-energy nuclear science and petascale computing, while advancing a web-database for research and educational purposes.The overarching goal is to learn from and inform experiments at radioactive beam facilities, and to predict properties of experimentally inaccessible nuclei that are key to advancing our knowledge about astrophysical processes. The program focuses on improving reaction modeling by constructing the effective interaction between a target and a projectile from first principles (historically, referred to as an optical potential and fitted to experimental data), which now account for the challenging microscopic structure of the participating nuclei. As these interactions are an essential input to numerous reaction models that are currently in use, the new developments serve as an important tool in a broad spectrum of studies. The project capitalizes on a symmetry-guided approach that, by exploiting symmetries known to dominate the dynamics, has enabled ab initio investigations of heavier nuclear species, deformed or not. In this approach, all participating particles are treated on the same footing within a "shell model" picture, while employing chiral effective field theory interactions between protons and neutrons. The end products include calculations of beta decays in nuclei of enhanced deformation, and of reaction observables, e.g., cross sections for scattering, charge-exchange, and (d,p) reactions, of importance to astrophysics.This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

核裂变的历史性发现表明，中子和质子之间的强力键断裂会释放出巨大的能量，继这一发现之后，核物理学家一直在寻找对原子核性质的更全面的解释。这些进展对于预测恒星合并和爆炸等极端条件下过程中的奇异核以及探测中微子相关过程至关重要。最近出现的放射性束设施使得基于核碰撞及其反应的外来核测量成为可能。为了预测不可接近的核，必须很好地理解和建模这些反应。然而，精确解最多存在五个粒子。该计划的目标是通过为基于第一原理的反应模拟提供输入，显着扩展核反应理论的能力，但也可以适应更重的核和增强的变形。这对于元素起源的研究非常重要，元素起源是当今物理学最大的挑战之一，并且由于核能应用和国家安全研究有类似的需求，因此具有更广泛的影响。未来的领导者（博士后和学生）接受低能核科学和千万亿级计算方面的培训，同时推进用于研究和教育目的的网络数据库。总体目标是从放射性束设施的实验中学习并为实验提供信息，并预测特性实验上无法接近的原子核对于增进我们对天体物理过程的了解至关重要。该项目的重点是通过根据第一原理（历史上称为光学势并适合实验数据）构建目标和射弹之间的有效相互作用来改进反应模型，现在该原理解释了参与核的具有挑战性的微观结构。由于这些相互作用是当前使用的众多反应模型的重要输入，因此新的发展成为广泛研究的重要工具。该项目利用了一种对称引导的方法，通过利用已知的主导动力学的对称性，可以对较重的核素（无论是否变形）进行从头开始的研究。在这种方法中，所有参与的粒子都在“壳模型”图中以相同的基础进行处理，同时采用质子和中子之间的手性有效场论相互作用。最终产品包括增强形变核中 β 衰变的计算，以及反应可观测值的计算，例如对天体物理学很重要的散射、电荷交换和 (d,p) 反应的横截面。该项目推进了“ “宇宙之窗：多信使天体物理学时代”，被列为NSF未来投资十大创意之一。该奖项体现了NSF的法定使命，经评估认为值得支持利用基金会的智力优势和更广泛的影响审查标准。

项目成果

Ab initio symmetry-adapted emulator for studying emergent collectivity and clustering in nuclei

• DOI: 10.3389/fphy.2023.1064601
• 发表时间: 2023-03
• 作者: K. S. Becker;K. Launey;A. Ekstrom;T. Dytrych

Emergent symmetries in atomic nuclei: Probing nuclear dynamics and physics beyond the standard model

原子核中的涌现对称性：超越标准模型探索核动力学和物理学

• DOI: 10.21468/scipostphysproc.14.007
• 发表时间: 2023
• 期刊: SciPost Physics Proceedings
• 作者: Launey, Kristina D.;Becker, K. S.;Sargsyan, G. H.;Molchanov, O. M.;Burrows, M.;Mercenne, A.;Dytrych, T.;Langr, D.;Draayer, J. P.
• 通讯作者: Draayer, J. P.

Ab initio single-neutron spectroscopic overlaps in lithium isotopes

• DOI: 10.1103/physrevc.108.054303
• 发表时间: 2022-10
• 期刊: Physical Review C
• 影响因子: 3.1
• 作者: G. Sargsyan;K. Launey;R. Shaffer;S. Marley;N. Dudeck;A. Mercenne;T. Dytrych;J. Draayer