RUI: Testing Fundamental Symmetries with Muon Experiments

RUI：用 μ 子实验测试基本对称性

• 批准号: 2209486
• 负责人: Frederick Gray
• 金额: $ 25.02万
• 依托单位: Regis University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2209486&HistoricalAwards=false
• 关键词: RUI; Testing; Fundamental; Symmetries; Muon

This award will support the Regis University group in continuing to probe one of the few known experimental discrepancies with the Standard Model of subatomic physics, which encodes our understanding of the fundamental building blocks of matter and energy. The Fermilab Muon g-2 experiment observes muons, which are subatomic particles that are like massive electrons, as they move through a magnetic field. It measures the rate at which the muons’ spin directions rotate; this rate is determined by the sum of the muons’ interactions of all kinds, potentially including interactions with new particles or via new kinds of forces that have not yet been discovered directly. The Standard Model makes a precise theoretical prediction; it differs from the recently-published result from the experiment’s first year of data collection at a level that may reveal the effects of new physical processes. A much larger data set has already been collected and is being analyzed, and one additional year of data collection is expected. Meanwhile, the precision of the Standard Model prediction is limited primarily by the uncertainty of the contributions to it from hadrons: particles that are composed of quarks and gluons, which are the domain of nuclear physics. The Regis group will participate substantially both in the completion of the Fermilab experiment and in the development of the MUonE experiment at CERN, which will measure the hadronic contributions with an independent method. Regis University’s physics program is undergraduate-focused, and this award will generate opportunities for physics majors and minors to become involved in leading-edge research in nuclear physics. They will develop laboratory, data analysis, and computing skills as they participate, with substantial mentoring, in the Muon g-2 and MUonE experiments. Furthermore, Regis University is a diverse campus, so many of the students who will be supported by this renewed grant are expected to be from groups that are currently underrepresented in the sciences.The Muon g-2 experiment will improve the precision of the measurement of the muon’s anomalous magnetic moment from 350 to 140 parts per billion (ppb), providing a window for discovery. Extending the experiment to the negative muon polarity in the final run, as is planned, will also allow for a precision test of CPT and Lorentz symmetries. The uncertainty associated with the Standard Model prediction, which is currently 370 ppb, will soon be the limiting factor in interpreting the Muon g-2 result. This uncertainty arises predominantly from the hadronic vacuum polarization component, which MUonE will determine from the running of the electromagnetic coupling (alpha) with energy scale in elastic scattering of a muon beam from target electrons. The Regis University group will continue to operate and analyze data from the “fiber harp” beam monitoring detectors in the Muon g-2 experiment, and to further develop the collaboration’s Monte Carlo simulations, which will be used to study questions related to the dynamic motion of the stored muon beam. The Regis group will also contribute to the completion of the technical proposal for the MUonE experiment and to its first physics data collection, initially taking on roles in the design, simulation, and testing of the electromagnetic calorimeter and other downstream detector components.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.

该奖项将支持瑞吉斯大学团队继续探索与亚原子物理学标准模型的少数已知实验差异之一，该标准模型编码了我们对物质和能量基本组成部分的理解。费米实验室的μ子g-2实验观察μ子，这是一种亚原子粒子，就像大质量的电子一样，当它们穿过磁场时。它测量μ子自旋方向旋转的速率;这个速率由μ子各种相互作用的总和决定，可能包括与新粒子的相互作用或通过尚未直接发现的新类型的力。标准模型做出了精确的理论预测;它与最近发表的实验第一年数据收集的结果不同，可能揭示了新物理过程的影响。已经收集并正在分析一个大得多的数据集，预计还将再收集一年的数据。与此同时，标准模型预测的精度主要受到强子贡献的不确定性的限制：强子是由夸克和胶子组成的粒子，这是核物理学的领域。瑞吉斯小组将实质性地参与费米实验室实验的完成和欧洲核子研究中心MUonE实验的开发，该实验将用独立的方法测量强子贡献。 瑞吉斯大学的物理课程以本科生为重点，该奖项将为物理专业和未成年人提供参与核物理前沿研究的机会。他们将发展实验室，数据分析和计算技能，因为他们参与，大量的指导，在μ on g-2和MUonE实验。此外，里吉斯大学是一个多元化的校园，因此，许多将获得新资助的学生预计将来自目前在科学界代表性不足的群体。μ子g-2实验将把μ子异常磁矩的测量精度从350 ppb提高到140 ppb，为发现提供了一个窗口。按照计划，在最后一次运行中将实验扩展到负μ子极性，也将允许CPT和洛伦兹对称性的精确测试。与标准模型预测相关的不确定性（目前为370 ppb）将很快成为解释Muon g-2结果的限制因素。这种不确定性主要来自强子真空极化分量，MUonE将从目标电子的μ子束弹性散射中的电磁耦合（α）与能量标度的运行中确定。瑞吉斯大学小组将继续操作和分析Muon g-2实验中“光纤竖琴”光束监测探测器的数据，并进一步开发合作的蒙特卡罗模拟，该模拟将用于研究与存储的μ子光束的动态运动相关的问题。 Regis小组还将为完成MUonE实验的技术提案及其首次物理数据收集做出贡献，最初将在设计，模拟，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进行评估，被认为值得支持的搜索.