Collaborative Research: Equipment for and Running of the PSI MUSE Experiment

亚原子物理学的一个基本目标是精确确定亚原子粒子的物理性质。质子的半径就是这些性质之一。半径可以通过从质子散射电子或介子来测量，或者通过测量氢或介子氢的能级来测量，氢或介子氢原子中的电子被介子取代。到目前为止，半径是通过电子的散射以及氢和介子氢的能级来测量的。缪子测量结果与电子测量结果不一致，这个问题被称为“质子半径之谜”。这种差异引起了广泛的关注，因为它可能表明存在以前没有观察到的和意想不到的Muon和电子相互作用之间的差异。瑞士Paul Scherrer研究所将进行一项专门的Muon质子散射实验(MUSE)，直接比较质子对Muon和电子的散射，该领域的专家们非常期待它能解决这个难题。该项目将包括MUSE实验探测器的几个关键部件的原型和开发。该项目将包括对本科生、研究生、博士后和初级教职员工的学生和青年科学家的培训。参与该项目的机构培训了大量各类学生，包括来自少数群体的学生。他们在做基础研究的过程中接受的培训导致了从医学物理到国家安全等各种领域的职业生涯，此外，他们还继续从事基础物理研究。缪斯实验将拓宽美国学生的视野，让他们在国际实验室的国际合作中工作，这将有效地为他们成为下一代杰出的全球科学家做好准备。随着人们对质子半径之谜的广泛兴趣，缪斯具有超越当前科学界的广泛灵感的潜力。实验使用了电子、介子和介子的混合束。测量要求精度高、系统误差小。该项目将建造和测试探测器系统的组件。其中包括用于测量入射粒子轨迹的闪烁光纤探测器、用于粒子识别的Cerenkov探测器、用于精确定位的宝石探测器、用于测量散射粒子轨迹的稻管探测器以及用于识别散射粒子的闪烁探测器。此外，还将开发一种液氢靶标。这些探测器的开发和测试将证明可以获得所需的精度。

A fundamental goal of subatomic physics is the precise determination of the physical properties of subatomic particles. The radius of the proton is one of these properties. The radius can be measured by scattering electrons or muons from protons, or by measuring the energy levels of hydrogen or muonic hydrogen, an atom in which the electron is replaced by a muon. To date, the radius has been measured by scattering of electrons, and by the energy levels of hydrogen and muonic hydrogen. The muonic measurements disagree with the electronic measurements, an issue known as "the proton radius puzzle." The discrepancy has attracted wide attention, because it may indicate the existence of previously unobserved and unexpected differences between the interactions of muons and electrons.A dedicated MUon proton Scattering Experiment (MUSE), which will run at the Paul Scherrer Institute in Switzerland and directly compare the scattering of muons and electrons from protons, is highly anticipated by experts in the field for its potential to resolve the puzzle. This project will cover the prototyping and development of several crucial components of the MUSE experiment detectors. This project will involve the training of students and young scientists, at the undergraduate, graduate, post-doctoral, and junior faculty levels. The institutions involved in this project have trained large numbers of students of each type, including from minority populations. The training they have received in the process of doing basic research has led to careers in a variety of areas, from medical physics to national security, in addition to continued work in fundamental physics research. The MUSE experiment will broaden the perspective of American students by having them work in an international collaboration at an international laboratory, which will prepare them effectively to become prominent global scientists of the next generation. With the broad interest in the proton radius puzzle, MUSE has the potential to be broadly inspirational beyond the current scientific community.The experiment uses a mixed beam of electrons, muons, and pions. The measurement requires high precision and small systematic errors. This project will build and test the components of the detector system. These include scintillation fiber detectors to measure the trajectories of incoming particles, Cerenkov detectors for particle identification, GEM detectors for precise positioning, straw tube detectors for measuring the trajectories of scattered particles, and scintillation detectors for particle identification of the scattered particles. In addition, a liquid hydrogen target will be developed. Development and testing of these detectors will demonstrate that the required precision can be obtained.