Multi-Probe Investigation of the Nucleon

核子的多探针研究

• 批准号: 2310026
• 负责人: Evangeline Downie
• 金额: $ 103.27万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310026&HistoricalAwards=false
• 关键词: Multi; Probe; Investigation; Nucleon

Protons, neutrons, and electrons are the building blocks of all matter with which we are most familiar. Despite the scientific efforts to comprehend their nature, there are many things about them that remain to be understood. In 2010, a measurement of the size of the proton gave a much smaller than expected result. This measurement disagreed with, but was much more precise than, all the other proton size measurements to date. Since that time, many other people have tried to re-measure the proton size using different approaches, but the discrepancy persists. The research supported by this award aims to resolve this issue, known as the "Proton Radius Puzzle" by making the first simultaneous measurement of muon and electron scattering on the proton in the Muon Proton Scattering Experiment (MUSE). Through this experiment, in addition to gaining knowledge about protons, the postdoctoral researcher, undergraduate, and graduate students will gain knowledge and experience of modern detection techniques, and simulation and reconstruction software, which are employed in many applications such as industrial or medical imaging. They will also participate in cultural exchanges with researchers from many countries worldwide, and develop their communication, organization, and leadership skills.MUSE will make the world's first measurement of the proton radius via elastic muon scattering at a precision which can address the 4% proton radius puzzle. The experiment will be performed at the Paul Scherer Institute in Switzerland. The simultaneous measurement of elastic e-plus / e-minus and mu-plus/mu-minus scattering on the proton in the MUSE experiment will allow resolution of the proton radius puzzle: the 7-sigma discrepancy between the charge radius of the proton measured in the excitation spectrum of muonic hydrogen and that measured in the excitation spectrum of the atomic hydrogen. Measuring with both electrons and muons simultaneously improves the systematic uncertainty, and provides a test of lepton universality. Measuring both charge states allows for the direct measurement and determination, and then cancellation, of any two-photon effects in both muon- and electron-scattering. This project involves participation in and leadership of data taking and analysis of MUSE through the support of the PI, a graduate student, undergraduate student, and a postdoc. It will result in precise, simultaneous elastic muon and electron scattering data.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.

质子、中子和电子是我们最熟悉的所有物质的组成部分。尽管科学界努力理解它们的本质，但关于它们的许多事情仍有待理解。 2010年，对质子尺寸的测量给出了比预期小得多的结果。该测量结果与迄今为止所有其他质子尺寸测量结果不一致，但更为精确。从那时起，许多其他人尝试使用不同的方法重新测量质子大小，但差异仍然存在。该奖项支持的研究旨在通过在μ子质子散射实验（MUSE）中首次同时测量质子上的μ子和电子散射来解决这个被称为“质子半径之谜”的问题。通过这个实验，除了获得有关质子的知识外，博士后研究员、本科生和研究生还将获得现代检测技术以及模拟和重建软件的知识和经验，这些技术在工业或医学成像等许多应用中都有应用。他们还将参与与世界许多国家的研究人员的文化交流，培养他们的沟通、组织和领导能力。MUSE将在世界上首次通过弹性μ子散射测量质子半径，其精度可以处理4%的质子半径拼图。该实验将在瑞士保罗谢勒研究所进行。在 MUSE 实验中同时测量质子上的弹性 e-plus / e-minus 和 mu-plus/mu-minus 散射将能够解决质子半径难题：测量的质子电荷半径之间的 7-sigma 差异μ子氢的激发光谱和原子氢的激发光谱中测量的结果。同时用电子和μ子进行测量提高了系统的不确定性，并提供了轻子普适性的测试。测量两种电荷状态可以直接测量和确定，然后消除μ子和电子散射中的任何双光子效应。 该项目涉及在 PI、一名研究生、本科生和一名博士后的支持下参与和领导 MUSE 的数据采集和分析。它将产生精确、同步的弹性μ介子和电子散射数据。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。