Research in Theoretical Nuclear and Neutrino Physics

探索可见物质的起源、演化和结构是现代科学的一个持续探索。最轻的元素是在大爆炸后的最初几分钟形成的，这一时期被称为大爆炸核合成（BBN）。BBN时代和恒星的持续演化，直到它们变成超新星，产生了铁等元素。大多数比铁重的元素被认为是由种子核捕获中子产生的。快速中子俘获过程（r-过程）的可能地点包括从超新星爆炸后形成的热中子星星表面蒸发的物质，两颗中子星的合并（最近首次观察到），以及伽马射线爆发中的吸积盘。不管元素形成过程的精确细节如何，我们需要的中子比质子多。上面列出的所有环境都含有大量的中微子，它们控制着中子与质子的比例。该项目将利用核物理学和天体物理学的工具，以及实验和观测数据，探索中微子性质与元素形成之间的相互作用。该项目将通过求解描述中微子集体振荡的多体方程，这是在具有足够高中微子密度的天体物理环境中由中微子-中微子相互作用引起的突发的非线性味演化现象。我们的目标是将我们的理论和计算工作与化学元素丰度的光学观测结合起来，以解释这些元素在宇宙中形成的位置。 PI和他的学生将探索中微子的性质，如质量，混合和偶极矩，并计算它们的捕获截面，以促进这一目标。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Exploring the origin, evolution and the structure of the visible matter is an ongoing quest of modern science. The lightest elements are formed during the first minutes after the Big Bang, the epoch known as the Big Bang Nucleosynthesis (BBN). The BBN epoch and the proceeding evolution of the stars until they go supernova produce elements up to iron. Most of the elements heavier than iron are thought to be produced by the capture of neutrons on seed nuclei. Possible sites of the rapid neutron capture process (r-process) include matter evaporated from the surface of a hot neutron star formed following a supernova explosion, the merging of two neutron stars (recently observed for the first time), and accretion disks in gamma-ray bursts. Irrespective of the precise details of the elements-formation process, one needs an abundance of neutrons over protons. All environments listed above also contain a very large number of neutrinos, which control the ratio of neutrons to protons. This project will explore the interplay between neutrino properties and the formation of elements using tools from nuclear physics and astrophysics, as well as experimental and observational data.This project will contribute to the description of neutrino transport in the r-process sites by solving the many-body equations describing collective oscillations of neutrinos, which are emergent nonlinear flavor evolution phenomena instigated by neutrino-neutrino interactions in astrophysical environments with sufficiently high neutrino densities. The goal is to bring together our theoretical and computational efforts with the optical observations of the abundances of chemical elements to explain where in the cosmos these elements are formed. The PI and his students will explore properties of neutrinos such as masses, mixings, and dipole moments and calculate their capture cross sections to facilitate this goal.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.