Nuclear, Particle, and Weak Interaction Physics of the Big Bang and Stellar Collapse

该项目支持的研究将为原子核、基本粒子和辐射在极端温度和密度条件下的行为提供见解。PI将利用这些见解来提供关于基本粒子的本质的重要线索，特别是神秘的中微子，以及元素在自然界中是如何合成的，例如，坍缩恒星或碰撞中子星火热内部最重的元素，以及早期宇宙中最初几秒钟最轻的元素。反过来，这些考虑可以让我们深入了解新的物理学。在这个项目中进行的计算将涉及将人类关于自然的基本理论，即量子力学，打磨成一种能够模拟宇宙提供的极端环境中中微子行为的工具。这个项目的另一个关键产品将是在研究生和本科两级培训年轻的核物理学家。本项目支持的研究将通过利用核物理学和中微子物理学令人兴奋的新发展的交叉点，以及多信使天文学和精确宇宙学的出现带来的新数据和见解的爆炸式增长，直接探索中微子和原子核的基本物理。这个项目的一个关键问题将是研究中微子如何在致密物质中相互作用，以及这些相互作用如何导致中微子改变它们的口味（例如，电子型中微子变成tau型，反之亦然）。这是一个非常非线性的问题，因为中微子的味道/自旋决定了中微子如何相互作用，它们如何相互作用决定了味道/自旋的变化。为此，P.I.和他的研究生和本科生将努力：(1)理解和建模在一般介质中控制中微子风味和自旋演化的量子动力学方程；(2)构建早期宇宙和致密天体环境中中微子风味/自旋演化的大规模数值模拟，评估这种中微子风味物理对这些场所的原子核合成前景的反馈，以及这种物理对多信使观测和暗扇区物理的影响；(3)了解核结构、中微子-核相互作用、核配分函数和高温环境下的核弱强度分布。该项目推进了“宇宙之窗：多信使天体物理学时代”的目标，这是美国国家科学基金会未来投资的十大理念之一。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。

The research supported in this project will provide insights into how atomic nuclei and elementary particles and radiation behave in extreme conditions of temperature and density. The PI will leverage these insights to provide important clues about the nature of elementary particles, the mysterious neutrinos in particular, and about how the elements are synthesized in nature, e.g., the heaviest elements in the fiery interiors of collapsing stars or colliding neutron stars, and the lightest in the first seconds in the early universe. In turn, these considerations can give us insight into new physics. The calculations to be done in this project will involve honing humanity's fundamental theory of nature, i.e., Quantum Mechanics, into a tool capable of modeling the behavior of neutrinos in the extreme environments provided by the cosmos. Another key product of this Project will be the training of young nuclear physicists, at both the graduate and undergraduate levels. The research supported in this Project will be directed toward probing the fundamental physics of neutrinos and nuclei by exploiting the intersection of exciting new developments in nuclear physics and neutrino physics on the one hand, with the explosion of new data and insights from the advent of multi-messenger astronomy and precision cosmology on the other. A key issue in this enterprise will be studying how neutrinos interact in dense matter and how these interactions may cause neutrinos to change their flavors (e.g., electron type neutrinos changing to tau type and vice versa). This is a fiercely nonlinear problem because neutrino flavor/spin determines how neutrinos interact, and how they interact determines how flavors/spin change. To these ends, the P.I. and his graduate and undergraduate students will work toward: (1) Understanding and modeling the quantum kinetic equations which govern neutrino flavor and spin evolution in a general medium; (2) Constructing large-scale numerical simulations of neutrino flavor/spin evolution in the early universe and compact object environments and assessing the feedback of this neutrino flavor physics on the prospects for the synthesis of nuclei in these sites, and the implications of this physics for multi-messenger observations and dark sector physics; (3) Understanding nuclear structure, neutrino-nucleus interactions, nuclear partition functions, and nuclear weak strength distributions in high temperature environments.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.