Methods for Data Analysis and Systematic Corrections in the Fermilab E989 Muon g-2 Experiment

该奖项支持数据采集和分析以及计算，从而能够精确测量μ子的磁性，从而测试粒子和相互作用的标准模型。μ子是一种亚原子粒子，与电子相似，但质量大约是电子的200倍。过去对μ子磁矩的测量与标准模型的预测不一致。磁矩是量化μ子与磁场相互作用的基本属性。该实验将在费米国家加速器实验室（Fermilab）进行，并利用磁场和电场将以接近光速运动的μ子限制在一个圆形存储环中。从数据中提取μ子的磁矩需要修正，以解释μ子通过的磁场的变化。这些修正的方法将根据本合同制定。除了在前沿实验和数据分析技术方面培训研究生外，该项目还将通过指导初高中学生进行顶点研究项目，将当地公立高中对物理科学感兴趣的学生与基础物理研究联系起来。对介子异常磁矩的测量和理论计算的高精度比较构成了对标准模型完整性的检验。在2001年完成数据采集的布鲁克海文E821实验中，μ子的异常磁矩被精确测量到百万分之0.54。该实验的结果与标准模型的理论值相差3.5个标准差。在2017年开始采集数据的费米实验室E989实验中，异常磁矩的精度将提高近四倍，达到0.14 ppm的水平，从而提供了确定新物理学证据的可能性，前提是实验和理论中心值没有显着变化。在实验中，相对论性的“魔动量”介子将被储存起来，随后在1.45特斯拉超导磁存储环内进行回旋加速器轨道，并使用电场进行限制。该奖项支持对μ子回旋加速器和自旋进动频率进行系统修正的工作，其差异与异常磁矩成正比，异常磁矩是由于μ子通过存储环体积上不可避免地存在的磁场中的小不均匀性和μ子通过电场的相对论性运动产生的磁场而产生的。建模和模拟这些系统效应的方法将由PI和该奖项下的一名研究生开发。

This award supports data taking and analysis as well as calculations that will enable the precise measurement of the muon's magnetic properties and thereby test the Standard Model of Particles and Interactions. Muons are subatomic particles that are like electrons but are about 200 times more massive. Past measurements of the muon's magnetic moment, a fundamental property that quantifies how it interacts with magnetic fields, disagree with predictions of the Standard Model. The experiment will take place at the Fermi National Accelerator Laboratory (Fermilab) and use muons moving at nearly the speed of light and confined in a circular storage ring using magnetic fields and electric fields. Extracting the muon's magnetic moment from the data will require corrections to account for variations in the magnetic fields through which the muons pass. Methods for these corrections will be developed under this award. In addition to the training of a graduate student in forefront experimental and data analysis techniques, this project will also connect students from local public high schools interested in the physical sciences with fundamental physics research, via the mentoring of junior- and senior-level students in capstone research projects. A high-precision comparison of measurements and theoretical calculations of the muon's anomalous magnetic moment constitutes a test of the completeness of the Standard Model. In the Brookhaven E821 experiment, which completed data taking in 2001, the muon's anomalous magnetic moment was measured to a precision of 0.54 parts-per-million (ppm). The result from that experiment lies some tantalizing ~3.5 standard deviations from the Standard Model theoretical value. In the Fermilab E989 experiment, which began data taking in 2017, the precision on the anomalous magnetic moment will be improved by nearly a factor of four to the level of 0.14 ppm, thus presenting the possibility for a definitive claim of evidence for new physics, provided the experimental and theoretical central values do not change significantly. In the experiment, relativistic "magic momentum" muons will be stored and subsequently undergo cyclotron orbits within a 1.45 Tesla superconducting magnetic storage ring, with electric fields employed for confinement. This award supports work on systematic corrections to the muon's cyclotron and spin precession frequencies, the difference of which is proportional to the anomalous magnetic moment, resulting from muon transport through the small non-uniformities in the magnetic fields inevitably present over the volume of the storage ring and the magnetic fields resulting from the muons' relativistic motion through the electric fields. Methods for modeling and simulating these systematic effects will be developed by the PI and a graduate student under this award.