NSF-BSF: Precision Muon and Electron Scattering to Probe Low-Energy Proton Structure

该奖项为国家科学基金会支持的PI及其团队在汉普顿大学的研究活动提供资金，汉普顿大学是美国弗吉尼亚州一所历史悠久的黑人学院和大学（HBCU）。该小组将在瑞士保罗-谢勒研究所进行μ子散射实验（MUSE）。MUSE实验是对所谓的“质子半径谜题”的调查。质子的大小是一个基本的量，由于相互矛盾的测量和方法，具有相当大的不确定性。MUSE实验将通过电子和介子对质子的弹性散射，高精度地测量质子的电荷半径。该实验将提供数据来限制对这个谜题的可能解释，并有可能揭示超出标准模型的新物理学。该项目为少数民族院校的学生和博士后提供参与国际前沿研究的机会。MUSE实验旨在解决迄今为止核与粒子科学中最紧迫的问题之一；来测量质子的半径。MUSE将使用任意一种电荷（μ+/e+, μ−/e−）的混合介子和电子束，在广泛的运动范围内精确测量轻子-质子弹性散射截面，目的是提取每个探针的质子电荷半径。该实验将以高精度确定电子散射与介子散射观察到的质子电荷半径是否存在差异。同时，它将对核理论提供严格的约束。PI是MUSE项目的最初发起者之一。coPI是一名初级教员，其博士研究的重点是类似的测量方法。该小组将在运行实验和分析数据方面发挥主要作用。值得注意的是，该小组负责使用GEM探测器对MUSE进行高分辨率光束粒子跟踪。更广泛的影响：PI的研究项目为少数民族学生（主要是非裔美国人）和博士后研究人员提供了新的研究和教育机会。汉普顿大学是美国唯一一所提供核物理博士课程的HBCU。该项目将汉普顿大学最先进的探测器开发与PSI和杰斐逊实验室等全球机构的前沿研究相结合。多年来，PI成功地与汉普顿大学的本科生和研究生合作，他一直是博士后研究人员的专业导师，也是女性在科学领域的坚定支持者。此外，PI还与其他机构保持着强有力的合作关系，其明确目标是吸引研究生到汉普顿大学攻读物理学博士和硕士课程，并为有才华的本科生提供进入顶尖学校接受研究生教育的渠道，最终增加非裔美国人博士的数量。用于MUSE的GEM探测器的开发和运行为推进这项新技术奠定了坚实的基础，该技术在其他实验以及医疗部门和国家安全方面具有潜在的应用前景。该项目由物理系和传统黑人学院和大学本科项目共同资助。该奖项还为以色列耶路撒冷希伯来大学的研究小组提供了两国科学基金会（BSF）的资助。该奖项反映了美国国家科学基金会的法定使命，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。

This award provides funding for the NSF-supported research activities of the PI and his group at Hampton University, a Historically Black College and University (HBCU) in Virginia, USA. The group will work on the Muon Scattering Experiment (MUSE) at the Paul-Scherrer Institute in Switzerland. The MUSE experiment is an investigation into the so-called “proton radius puzzle”. The size of the proton is a fundamental quantity with considerable uncertainty due to conflicting measurements and methods. The MUSE experiment will measure the proton charge radius with high precision via the elastic scattering of electrons and muons off protons. The experiment will provide data to constrain the possible explanations of the puzzle and has the potential to reveal new physics beyond the Standard Model. The project offers opportunities for students and postdocs at a minority serving institution to participate in forefront international research.The MUSE experiment aims to address one of the most pressing questions in nuclear and particle science to date; to measure the radius of the proton. MUSE will use mixed muon and electron beams of either charge (μ+/e+, μ−/e−) to make precise measurements of the lepton-proton elastic scattering cross sections, over a broad kinematic range, with the goal to extract the proton charge radius for each probe. The experiment will determine, with high precision, if there is any difference seen for the proton charge radius observed by electron versus muon scattering. At the same time, it will provide tight constraints on nuclear theory. The PI is one of the original initiators of the MUSE project. The coPI is a junior faculty member whose PhD work focused on similar measurements. The group will play a major role in running the experiment and analyzing the data. Notably, the group is responsible for high-resolution beam particle tracking at MUSE using GEM detectors.Broader Impact: the PI’s research program provides new research and educational opportunities for students from minority populations, predominantly African-Americans, and postdoctoral researchers. Hampton University is the only HBCU in the US offering a PhD program in Nuclear Physics. This project combines state-of-the-art detector development at Hampton University with forefront research at facilities around the globe, such as PSI and Jefferson Lab. The PI has successfully worked with Hampton University undergraduate and graduate students for many years, and he has been a dedicated mentor for postdoctoral researchers and a strong supporter of women in science. Further, the PI has maintained strong partnerships with other institutions, with the clear goal of attracting graduate students to the physics PhD and Master programs at Hampton University and providing a pipeline of talented undergraduate students toward graduate education in top schools, to ultimately increase the number of African-American PhDs. The development and operation of GEM detectors for MUSE constitutes a strong basis to advance this novel technology with potential future applications in other experiments, as well as in the medical sector and national security.The project is co-funded by the Physics Division, and the Historically Black Colleges and Universities Undergraduate Program. This award also provides Binational Science Foundation (BSF) funding for the group at The Hebrew University of Jerusalem, Israel.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.