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RUI: Testing Fundamental Symmetries with Muon g-2

RUI：用 Muon g-2 测试基本对称性

基本信息

批准号：
1811832
负责人：
Frederick Gray
金额：
$ 17万
依托单位：
Regis University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1811832&HistoricalAwards=false
关键词：
RUI Testing Fundamental Symmetries Muon

项目摘要

This award will support the PI and undergraduate students from Regis University to enable them to contribute to the Muon g-2 Experiment at Fermilab, which aims to discover new particles and interactions that are beyond the current Standard Model. The Standard Model of subatomic physics provides an overarching theoretical framework that describes all known forces except gravity. It has been extensively tested, and it successfully predicts almost every phenomenon that has ever been observed in experiments at particle accelerators. Nevertheless, it is known to be incomplete, since it does not have a way to explain dark matter or dark energy, and it does not account for the asymmetry of matter over antimatter that allowed the structures of our universe to form. Muons are in many ways similar to electrons, but with a mass approximately 207 times higher, and they are unstable, decaying in a few microseconds; they appear in nature as cosmic rays. The Muon g-2 Experiment measures the rate at which the of muons rotate as they orbit in a magnetic field. That rotation could arise from the coupling of muons to new particles. The experiment has been constructed and has completed its first year of data collection. With close mentoring from the PI and other collaborators, students will maintain and upgrade particle detectors, assist with taking data at Fermilab, and analyze data. They will have opportunities to present their work at conferences and collaboration meetings. The professional development of these students is a primary focus of this project. Entering classes at Regis University are continuing a trend of increasing ethnic and socioeconomic diversity, so the students supported by this award represent a broadening in the participation by groups that are currently underrepresented in physics research.The Muon g-2 experiment measures the muon's anomalous magnetic moment. Previous measurements of this quantity differ from theoretical predictions by about 3.5 standard deviations. The new measurement at Fermilab will record 20 times more muon decays than experiment 821 at Brookhaven National Laboratory. Systematic uncertainties will also be reduced, leading to an expected precision of 140 parts per billion. Consequently, the experiment has the potential to discover the indirect effects of new particles and interactions with very high statistical significance. The range of possible new physics is wide; it could include ideas such as supersymmetry, light weakly-interacting particles from a "dark sector," axion-like particles, or extra dimensions. Conversely, if the result turns out to agree with the Standard Model, it would provide a strong constraint on all of these new physics models. The experiment measures the rate of spin precession in flight for a muon beam in a weak-focusing 1.5 Tesla storage ring magnet. Several beam dynamics effects directly contribute to the systematic error, including coherent betatron oscillations (CBO) and muon losses, which are partly driven by the CBO. The fiber harps, which were refurbished and are maintained by the Regis group, are used to characterize and to minimize the CBO. The anticipated precision of the experiment assumes that the systematic errors from CBO and muon losses will be reduced by factors of 2.3 and 4.5, respectively. The Regis group participates in the analysis of fiber harp data in order to understand these beam dynamics effects; it also contributes to other parts of the analysis effort, including data quality control and run selection.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.

该奖项将支持来自瑞吉斯大学的PI和本科生，使他们能够为费米实验室的Muon g-2实验做出贡献，该实验旨在发现超越当前标准模型的新粒子和相互作用。亚原子物理学的标准模型提供了一个总体理论框架，描述了除引力之外的所有已知力。它已经过广泛的测试，并且成功地预测了在粒子加速器实验中观察到的几乎所有现象。然而，它是不完整的，因为它没有办法解释暗物质或暗能量，也没有解释物质与反物质的不对称性，而正是这种不对称性使得我们的宇宙结构得以形成。 μ子在许多方面类似于电子，但质量大约是电子的207倍，并且它们不稳定，在几微秒内衰减;它们在自然界中以宇宙射线的形式出现。 μ子g-2实验测量μ子在磁场中旋转的速率。这种旋转可能是由μ子与新粒子的耦合引起的。该实验已经建立，并已完成第一年的数据收集。在PI和其他合作者的密切指导下，学生将维护和升级粒子探测器，协助在费米实验室获取数据并分析数据。他们将有机会在会议和合作会议上介绍他们的工作。这些学生的专业发展是这个项目的主要重点。进入瑞吉斯大学的学生继续保持种族和社会经济多样性的趋势，因此获得该奖项的学生代表了目前在物理学研究中代表性不足的群体的参与。μ介子g-2实验测量μ介子的异常磁矩。以前对这个量的测量与理论预测相差约3.5个标准差。费米实验室的新测量将记录比布鲁克海文国家实验室821实验多20倍的μ子衰变。系统的不确定性也将减少，预计精度将达到十亿分之140。因此，该实验有可能发现新粒子的间接效应和具有非常高统计意义的相互作用。可能的新物理学的范围很广;它可能包括诸如超对称、来自“暗区”的弱相互作用的轻粒子、类轴子粒子或额外维度等想法。相反，如果结果与标准模型一致，它将对所有这些新的物理模型提供强有力的约束。该实验测量了弱聚焦1.5特斯拉存储环磁体中μ子束飞行中的自旋进动速率。几种束流动力学效应直接导致系统误差，包括相干电子感应加速器振荡（CBO）和μ子损失，这部分是由CBO驱动的。纤维竖琴，这是翻新和维护的瑞吉斯集团，是用来表征和尽量减少CBO。实验的预期精度假设来自CBO和μ子损失的系统误差将分别减少2.3和4.5倍。 Regis小组参与了光纤竖琴数据的分析，以了解这些光束动力学效应;它还对分析工作的其他部分做出了贡献，包括数据质量控制和运行选择。该奖项反映了NSF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。