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Muon的磁性，从而测试粒子和相互作用的标准模型。µ子是亚原子粒子，类似于电子，但质量大约是电子的200倍。过去对Muon磁矩的测量与标准模型的预测不一致。Muon的磁矩是量化其与磁场相互作用的基本属性。这项实验将在费米国家加速器实验室(Fermilab)进行，使用的是近光速运动的介子，并利用磁场和电场将其限制在圆形存储环中。从数据中提取Muon的磁矩将需要进行修正，以考虑到Muon通过的磁场的变化。这些纠正的方法将在本奖项下制定。除了对一名研究生进行前沿实验和数据分析技术培训外，该项目还将通过辅导Capstone研究项目中的初级和高级学生，将对物理科学感兴趣的当地公立高中的学生与基础物理研究联系起来。对介子反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测试。在2001年完成数据采集的布鲁克海文E821实验中，Muon的反常磁矩被测量到了0.54 ppm的精度。那个实验的结果与标准模型的理论值有一些诱人的~3.5标准偏差。在2017年开始采集数据的费米拉E989实验中，异常磁矩的精度将提高近四倍，达到0.14ppm的水平，从而提供了明确声称新物理证据的可能性，前提是实验和理论中心值没有显著变化。在这项实验中，相对论的“魔力”介子将被储存起来，然后在1.45特斯拉超导磁存储环内经历回旋轨道，并使用电场进行限制。该奖项支持对Muon的回旋和自旋进动频率进行系统校正的工作，这些频率的差异与反常磁矩成正比，这是由于Muon通过存储环体积上不可避免地存在的磁场中的小的不均匀传输而产生的，以及由于Muon在电场中的相对论运动而产生的磁场。这些系统效应的建模和模拟方法将由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.