Research in Theoretical Hadronic Physics and Related Topics

核物理学是研究原子核成分（质子和中子）以及将它们结合在一起的相互作用的物理学领域。在这种情况下，这个项目将调查在核理论感兴趣的一些基本课题。具体而言，该项目将侧重于更好地了解质子结构。其中一个突出的问题是质子电荷半径之谜，这是由使用电子和μ子的测量产生不同的质子电荷半径值这一事实引发的。为了解决这个难题，PI和他的合作者将计算理解在托马斯杰斐逊国家加速器设施（JLab）（美国）进行的实验和在JParc（日本）提出的实验所需的关键校正。PI将邀请本科生参与这些项目，并继续促进大学和国家实验室（特别是W M和JLab）之间的研究联系。该项目将研究μ子He-4中兰姆位移的核结构相关修正，支持将导致质子半径之谜的μ子氢兰姆位移测量扩展到He-4。 该项目还将研究轻质量μ子特定新粒子的模型，寻求一种包含对此类粒子的约束的模型，追求受Froggatt和Nielsen建议启发的第一个模型。 关于π形因子，它们是在反应e+ p-e π n中测量的，外推到π极，以及必须建模的非极项的背景。鉴于相关的π + p -（轻子对）+ n过程预计在JParc，PI和他的合作者将在数字上明确相关的背景。 PI还将研究扭曲光子，其具有结构化波前，允许运动方向上的高角动量（许多h巴），并且可以在强子尺度能量下产生。该奖项反映了NSF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。

Nuclear Physics is the field of physics that studies the atomic nucleus constituents (protons and neutrons) and the interactions that hold them together. In this context, this project will investigate a number of fundamental topics of interest in nuclear theory. Specifically, the project will focus on providing a better understanding of the proton structure. One of the outstanding problems is the proton charge radius puzzle, triggered by the fact that measurements using electrons and muons give rise to different values of the proton charge radius. Seeking a resolution to this puzzle, the PI and his collaborators will calculate crucial corrections needed to understand experiments performed at the Thomas Jefferson National Accelerator Facility (JLab) (USA) and experiments proposed at JParc (Japan). The PI will involve undergraduate students in these projects, and continue fostering research connections between universities and national labs (especially W&M and JLab).This project will study nuclear structure-dependent corrections to the Lamb shift in muonic He-4, supporting the extension to He-4 of the muonic hydrogen Lamb shift measurements which led to the proton radius puzzle. This project will also study models for light mass muon specific new particles, seeking a model that would encompass the constraints on such particles, pursuing first models inspired by suggestions of Froggatt and Nielsen. Regarding pion form factors, they are measured in the reaction e+ p - e pi n, with an extrapolation to the pion pole, and a background from non-pole terms that must be modeled. Given that the related pi + p - (lepton pair) + n process is anticipated at JParc, the PI and his collaborators will make numerically clear the relevant backgrounds. The PI will also study twisted photons, which have structured wave fronts that allow high angular momentum (many h-bar) in the direction of motion, and which can be produced at hadron scale energies.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.