Windows on the Universe: Study of Open Quantum Systems in Atomic Nuclei

该奖项支持研究质子和中子在中子远多于质子的原子核中如何相互作用，也被称为稀有同位素。这些富含中子的稀有同位素跨越了存在的极限，它定义了中子滴线，在那里质子和中子不再形成原子核，因为它们变得能量不受束缚。这些同位素的结构和性质与理解天体物理过程有关。这项研究将在包括国家超导回旋加速器实验室（NSCL）在内的科学用户设施中进行，该实验室很快将成为稀有同位素光束设施（FRIB）。该研究计划的一部分将与MoNA探测器和MoNA合作进行，该合作由一组本科院校组成，这些院校对招收STEM领域的学生产生了重大影响。该奖项包括支持来自hbcu和其他少数民族服务机构的学生和教师前往NSCL/FRIB并在夏季进行为期两周的实验合作。该奖项支持弱束缚原子核的实验研究，以测试与理解开放量子系统和宇宙天体物理过程相关的核模型。在多信使天文学时代，对连续体效应的正确建模和理解是很重要的，在这个时代，核性质，如结合能，与解释光学、中微子和引力波观测有关。它将解决一些基本问题，比如中子和质子的什么组合可以形成原子核，也许还能使我们对中子滴线的了解翻一番。该团队将使用MoNA协作的强大工具以及在FRIB可获得的广泛的新原子核来测量非束缚态的性质。利用准弹性质子去除反应来探测粒子发射阈值附近的状态和弱束缚核的结构的新技术将得到发展。最后，由于感兴趣状态的开量子性质，产生这些状态的反应机制成为测量的重要组成部分。在开放量子系统的背景下，将探讨反应机制的作用。该奖项旨在解决并推进“宇宙之窗大构想”的目标。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award supports research to understand how protons and neutrons interact when they are in a nucleus having far more neutrons than protons, also known as rare isotopes. These neutron-rich rare isotopes straddle the limit of existence, which defines the neutron drip line, where protons and neutrons no longer form a nucleus because they become energetically unbound. The structure and properties of these isotopes are relevant for understanding astrophysical processes. This research will be conducted at scientific user facilities including the National Superconducting Cyclotron Laboratory (NSCL), soon to become the Facility for Rare Isotope Beams (FRIB). Part of this research program will be performed with the MoNA detector and the MoNA Collaboration, which consists of a group of undergraduate institutions that has had a major impact on recruiting students to STEM fields. The award includes support for students and faculty from HBCUs and other Minority Serving Institutions to go to NSCL/FRIB and collaborate on experiments for two-week long periods in the summer. This award supports experimental studies of weakly bound atomic nuclei in order to test nuclear models that are relevant to understanding open quantum systems and astrophysical processes in the universe. Proper modeling and understanding of continuum effects are important in the era of multi-messenger astronomy where nuclear properties, such as binding energies, are relevant for interpreting optical, neutrino, and gravitational-wave observations. It will address fundamental questions, such as what combination of neutrons and protons can form an atomic nucleus and perhaps double our knowledge of the neutron drip line. The team will use the powerful tools of the MoNA Collaboration along with the wide range of new nuclei accessible at FRIB to measure properties of unbound states. New techniques will be developed to exploit quasi-elastic proton removal reactions to probe states near the particle emission threshold and the structure of weakly-bound nuclei. Finally, due to the open-quantum nature of the states of interest, the reaction mechanism to produce these states becomes an important part of the measurement. The role of the reaction mechanism in the context of open quantum systems will be explored.This award addresses and advances the goals of the Windows on the Universe Big Idea.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.