Research in Theoretical Hadronic Physics and Related Topics

核物理是研究原子核成分(质子和中子)以及将它们结合在一起的相互作用的物理领域。在此背景下，该项目将调查核理论中感兴趣的一些基本主题。具体地说，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，引发这一谜题的原因是，使用电子和µ子进行测量会导致质子电荷半径的值不同。为了寻求这个谜题的解决方案，PI和他的合作者将计算出理解在托马斯·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修正。PI将让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&amp；M和JLab)之间的研究联系。该项目将研究与核结构有关的对Muonic He-4中Lamb位移的修正，支持将导致质子半径之谜的Muonic氢Lamb位移测量扩展到He-4。该项目还将研究质量较轻的介子特定新粒子的模型，寻找一种包含对此类粒子的约束的模型，寻求受弗罗加特和尼尔森建议启发的第一个模型。关于介子形状因子，它们是在反应e+p-e pi n中测量的，并外推到介子极点，以及必须建模的非极项的背景。鉴于相关的pi+p-(轻子对)+n过程预计将在JParc进行，PI和他的合作者将从数字上阐明相关背景。PI还将研究扭曲光子，它具有结构波阵面，允许运动方向上的高角动量(许多H-bar)，并且可以在强子尺度的能量下产生。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。

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.