Nuclear physics of the dynamic origin of the elements

元素动态起源的核物理学

• 批准号: SAPPJ-2021-00032
• 负责人: Ruiz, Chris
• 金额: $ 6.92万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 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=764749
• 关键词: Nuclear; physics; dynamic; origin; elements

Thanks to new observations and greatly enhanced simulation capabilities, nuclear astrophysics has recently discovered that the puzzle still surrounding the origin of many elements is likely due to their dynamic and violent origin in stellar nuclear production sites that defy simple approaches. In the past few years such dynamic scenarios have been identified to explain e.g. the abundances of the most metal-poor stars, as well as the origin of odd-Z elements, in the galactic chemical evolution of the Milky Way. These scenarios include the intermediate neutron-capture process (i-process) in convective interactions of the H and He shells in rapidly accreting white dwarfs or very metal-poor massive stars, or the convective-reactive nucleosynthesis in the merger of the O- and C-burning shells in massive stars. The recent discovery of gravitational waves from neutron-star mergers and the associated observation of the electro-magnetic counterpart of the light likely from decaying unstable species has firmly established the role of dynamic nucleosynthesis for the rapid neutron-capture process (r-process). The importance of these dynamic nuclear production sites has put forth the need for improved nuclear data for unstable species. The short lifetime of radioactive isotopes has seriously limited in the past the experimentally available information on nuclear data, such as cross sections and nuclear masses. Now, with new experimental facilities such as ARIEL at TRIUMF, FRIB and other facilities in Europe huge progress can be made by targeted, high-impact experiments that provide critical nuclear data to enable astrophysics simulation to distinguish between different scenarios of the dynamic origin of the elements in stars and stellar explosions.    This project will combine the astrophysics and nucleosynthesis simulation capabilities of an experienced senior researcher who will work on four projects, each of which focusses on a different dynamic nucleosynthesis environment. Each of these projects will be carried out with graduate students who will spend one half of the period of the project (three years) on this simulation and modelling effort, while the other half will be dedicated to nuclear physics experiments in the corresponding area. In each of these areas nuclear data, as it becomes available, will be implemented into the latest generation of astrophysical simulation and confronted with observations to maximize the impact of the nuclear physics experiments. Other than the science outcome, another main goal of this project is to transfer the skill of nuclear physics impact studies for astrophysics applications to a new generation of young nuclear physics researchers. This skill is relatively rare, yet the impact of the Canadian and international nuclear astrophysics programs involving radioactive beams critically depends on this type of activity.

感谢新的观察结果和大大增强的模拟功能，核天体物理学最近发现，仍然围绕许多元素起源的难题可能是由于它们在恒星核生产地点的动态和暴力起源，这无视简单的方法。在过去的几年中，已经确定了这样的动态场景来解释例如在银河系的银河化学演化中，最贫穷的恒星以及奇数元素的起源的丰度。这些情况包括在迅速闻名的白色矮人或非常金属贫困的大型恒星中的H和HE壳的中间中子捕获过程（I-PROCESS），或者在大型恒星中O-和C燃烧壳的合并中的对流反应性核肌动蛋白。最新发现中子星级合并引力波以及对衰减不稳定物种可能产生的电磁对应物的相关观察，最终确定了动态核旋转酶在快速中子捕获过程（R-Process）中的作用。这些动态核生产地点的重要性提出了需要改善不稳定物种的核数据。过去，放射性同位素的短寿命在过去严重限制了核数据，例如横截面和核质量的实验可用信息。现在，借助Triumf的Ariel等新的实验设施，FRIB和欧洲的其他设施可以通过有针对性的高影响力实验来实现巨大的进步，这些实验提供了关键的核数据，以使天体物理学模拟能够区分恒星和恒星爆炸元素的动态起源的不同场景。该项目将结合一位经验丰富的高级研究人员的天体物理学和核骨干模拟能力，该研究人员将在四个项目上工作，每个项目都集中在不同的动态核骨识环境上。这些项目中的每一个都将与研究生一起进行，他们将花费该项目的一半（三年）进行此模拟和建模工作，而另一半将致力于相应领域的核物理实验。在这些领域中，核数据可用，将实施到最新一代的天体物理模拟中，并面临观察结果，以最大程度地提高核物理实验的影响。除了科学的结果外，该项目的另一个主要目标是将核物理学的技能转移到新一代的年轻核物理研究人员中。这种技能相对较少，但是加拿大和国际核天体物理学计划的影响涉及放射性光束，这在很大程度上取决于这种活动。