Studies of the Structure of the Nucleon

这个奖项给罗格斯大学中间能源核物理组，使教授。吉尔曼和兰塞姆以及他们的研究生和本科生研究核子的结构。重点是质子的形状-质子的电荷是如何分布的。它包括对一个备受瞩目的难题的研究：当用两种类型的粒子（电子和μ子）测量时，质子的大小是否相同。μ子是具有与电子相同特性但质量更大的粒子。除了该项目的直接科学目标外，实验还为本科生和研究生以及其他早期职业科学家提供现代科学实验国际合作的经验和培训，以及最先进的技术。这笔赠款将支持罗格斯大学中能实验核物理组的实验核物理研究计划的继续。活动的重点是MUSE，这是在瑞士Paul Scherrer研究所的PiM 1束线上进行的一项测量，用于测量液氢靶的正负电荷电子和μ子的散射截面。在此授权期间，该小组将继续获取生产数据，并开始分析阶段。散射截面被用来确定质子的形状因子，从中可以提取的质子电荷半径。该小组将比较带正电和带负电的粒子的散射，以确定双光子交换校正，并比较μ子与电子的散射，以确定质子半径是否相同。除了MUSE的新测量之外，该小组将继续在较低级别上参与分析和公布以前运行的实验结果。该小组的广泛影响主要是在本科生，研究生和博士后的培训。与该组织合作的学生和博士后除了继续从事基础物理学研究外，还在医学物理学、国家安全和金融系统等各个领域开展了工作。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。

This award to the Rutgers University Intermediate Energy Nuclear Physics group enables Profs. Gilman and Ransome and their graduate and undergraduate students to study the structure of the nucleon. The focus is on the shape of the proton - how the proton's charge is distributed. It includes the study of a high-profile puzzle: whether the proton size is the same when measured with two types of particles, electrons and muons. Muons are particles with the same characteristics as electrons but with more mass. In addition to the direct scientific goals of the project, the experiments provide undergraduate and graduate students and other early career scientists experience and training in working in international collaborations of modern scientific experiments, with state-of-the-art technology.This grant will support the continuation of the experimental nuclear physics research program of the intermediate energy experimental nuclear physics group at Rutgers University. The focus of the activities is MUSE, a measurement of the scattering cross sections of both positively and negatively charged electrons and muons from a liquid hydrogen target, performed at the PiM1 beam line of the Paul Scherrer Institute in Switzerland. During this grant period the group will continue taking production data and begin the analysis phase. The scattering cross sections are used to determine the proton form factors, from which the proton charge radius can be extracted. The group will compare scattering of positively and negatively charged particles to determine two-photon exchange corrections, and compare scattering of muons to electrons to determine if the proton radius is the same when determined by the two particles. In addition to the new measurements of MUSE, the group will continue to be involved at a lower level in the analysis and publication of results of experiments run previously. The broader impact of the group has been primarily in the training of undergraduates, graduates, and postdocs. Students and post-docs who have worked with the group have gone on to careers in a variety of areas, including medical physics, national security, and financial systems, in addition to continued work in fundamental physics research.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.