Hadronic Physics for Neutrino-Nucleon Interactions

现代核物理和粒子物理学关注于理解自然的基本参数和对称性。夸克是通过强力相互作用的粒子，强力将它们结合在一个原子核中。轻子感觉不到这种力；最常见的轻子例子是通过电磁相互作用与原子核结合的电子。一个更奇特的轻子是中微子，它不带电荷，相互作用很弱。 然而，这种难以捉摸的粒子被证明是我们寻找新物理现象的关键一环。过去二十年的精密实验测量揭示了中微子具有小但不为零的质量。 今天，中微子物理领域进入了精确时代，基于加速器的中微子振荡实验在美国和世界的实验计划中占据了中心位置。人们希望，夸克和轻子部门的综合精确数据有朝一日将为揭示潜在物理的性质提供关键。该项目提供了支持这些实验突破所需的理论基础，特别是通过对中微子-原子核相互作用进行更严格的描述。它也是学生们的一个极好的训练场。这项研究的重点是在模拟GeV能量下的中微子相互作用中起关键作用的一个特定的物理部分：核子轴向形状因子。它描述了核子的结构，它不是一个点状粒子，但具有一种仍然不为人所知的结构。PI和她的合作者基于手征微扰理论和色散技术开发了一个分析框架来准确地模拟这种形状因子。此外，通过应用各种分析约束，如电流守恒，建立了在晶格上进行数值计算的桥梁。对各种电子散射数据的一致性也进行了探讨。这些研究被扩展到中微子-核子散射中的介子产生，需要在依赖手征微扰对称性的低能知识和高能之间建立一座桥梁。这项研究支持托马斯·杰斐逊实验室最先进的核物理实验，特别是GlueX或Clas，以及即将在费米实验室和世界范围内进行的精密中微子-原子核散射实验。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Modern nuclear and particle physics are concerned with understanding the fundamental parameters and symmetries of nature. Quarks are particles that interact via the strong force, which binds them together in an atomic nucleus. Leptons do not feel this force; the most familiar example of a lepton is the electron that binds to the nucleus by the electromagnetic interaction. A more exotic lepton is the neutrino, which has no electric charge and interacts only weakly.  Yet, this elusive particle is proving to be a crucial link in our search for new physics phenomena. Exquisite experimental measurements over the last two decades revealed that the neutrinos have small but nonzero masses. Today, the field of neutrino physics enters a precision era, with accelerator-based neutrino oscillation experiments taking center stage in the experimental program in the US and in the world. It is hoped that the combined precision data from the quark and lepton sectors will one day provide a key to the nature of the underlying physics. This project provides theoretical foundations needed to support these experimental breakthroughs, in particular, by giving a more rigorous description of neutrino-nucleus interactions. It also serves as an excellent training ground for students. This research focuses on a specific piece of physics that plays a crucial role in modelling neutrino interactions at GeV energies: the nucleon axial form factor. It describes the structure of the nucleon which is not a point-like particle but has a structure that is still not well known. The PI and her collaborators develop an analytical framework to accurately model this form factor, based on the methods of chiral perturbation theory and dispersive techniques. Moreover, a bridge to numerical evaluations on the lattice is established by applications of various analytical constraints, such as current conservation. Agreement with various electron scattering data is also explored. These studies are extended to pion production in neutrino-nucleon scattering where a bridge between the low energy knowledge relying on chiral perturbation symmetry and higher energies needs to be established. This research supports the state-of-the-art nuclear physics experiments at Thomas Jefferson Laboratory, particularly GlueX or CLAS, as well as the upcoming precision neutrino-nucleus scattering experiments at Fermilab and worldwide.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.