Precision Measurements in Intermediate Energy Physics

中间能量物理的精密测量

• 批准号: 1206528
• 负责人: B. Lee Roberts
• 金额: $ 156万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206528&HistoricalAwards=false
• 关键词: Precision; Measurements; Intermediate; Energy; Physics

This award will support our group's leadership of two major new experiments at the Fermi National Accelerator Laboratory (Fermilab): Mu2e, and muon g-2 (E989). The Mu2e experiment at Fermilab, co-led by J. Miller will search for the lepton flavor violating (LFV) muon to electron conversion reaction at the 10^{-16} level, a factor of 10,000 times more sensitive than the present limit. B.L. Roberts is co-leading the muon g-2 experiment. Both experiments involve a dipole operator, and in the context of supersymmetry probe complementary aspects of that particular beyond-the-SM (BSM) theory. Mu2e is sensitive to a wider range of physics than the LFV decay of the positive muon to a photon and positron, which must go through the dipole interaction. The muon anomalous magnetic moment (g-2) is also sensitive to a wide range of BSM physics. It is a chiral-changing, flavor-diagonal interaction, which could have contributions from the chargino and neutralino in SUSY, or the "dark photon" from a hidden U(1) sector, or from Randall-Sundrum models. At present the difference between the SM and the Brookhaven experiment is around 3.5 standard deviations. Fermilab E989 is designed to cross the five standard deviation threshold. Whatever the result from Fermilab E989, it will provide an important constraint on the interpretation of new phenomena found at the LHC. The MuSun experiment is measuring the weak matrix element for muon capture on deuterium, which is related to the weak pp fusion matrix element that powers the sun.This award will support our group's leadership of two major new experiments at the Fermi National Accelerator Laboratory (Fermilab): Mu2e and muon g-2. It will also support our participation in two other experiments: the MuSun experiment at the Paul Scherrer Institute in Switzerland and the neutron electric dipole moment (EDM) experiment being prepared for Oak Ridge National Laboratory. J. Miller is co-leading the Fermilab Mu2e experiment that will search for the conversion of a muon into an electron without the emission of neutrinos. B.L. Roberts is co-leading the Fermilab muon g-2 experiment which will measure the magnetism associated with the muon a factor of four times more precisely than the previous experiment at the Brookhaven National Laboratory. Both of these experiments are looking for evidence of New Physics that cannot be explained by the Standard Model, a theory that at present describes all measured quantities in particle physics, but is known to be incomplete. Results from the previous g-2 experiment show a hint of something new, which should be clarified by the Fermilab experiment. This program is complementary to the searches at the energy frontier at the Large Hadron Collider in Geneva Switzerland. R. Carey is working on the MuSun experiment, which measures the rate at which a negative muon captures on the deuterium nucleus (made up of a proton and neutron), and breaks it apart by changing the proton into a neutron. This process is interesting since it can be related to the fusion of two protons together to form deuterium, the "burning of hydrogen" that powers the sun.

该奖项将支持我们的团队在费米国家加速器实验室（Fermilab）的两个主要新实验的领导：Mu 2 e和Muon g-2（E989）。由J.米勒共同领导的费米实验室的μ 2 e实验将在10^{-16}水平上寻找轻子味破坏（LFV）μ子到电子的转换反应，这是目前极限的10，000倍。B.L.罗伯茨是μ介子g-2实验的共同领导者。这两个实验都涉及偶极算符，并且在超对称性的背景下探索了该特定超越SM（BSM）理论的互补方面。 Mu 2 e对比正μ子到光子和正电子的LFV衰变更广泛的物理范围敏感，这必须通过偶极相互作用。 μ子反常磁矩（g-2）也对广泛的BSM物理敏感。 这是一种手征变化的、味对角相互作用，可能来自超对称性中的电荷伴子和中性伴子，或者来自隐藏的U（1）扇区的“暗光子”，或者来自兰德尔-桑德拉姆模型。目前，SM和Brookhaven实验之间的差异约为3.5个标准差。Fermilab E989旨在跨越五个标准差阈值。无论费米实验室E989的结果如何，它都将对LHC发现的新现象的解释提供重要的约束。 MuSun实验是测量氘上μ子捕获的弱矩阵元素，这与为太阳提供动力的弱pp聚变矩阵元素有关。该奖项将支持我们团队在费米国家加速器实验室（Fermilab）的两个主要新实验的领导地位：Mu 2 e和μ子g-2。它还将支持我们参与另外两项实验：瑞士保罗·谢勒研究所的MuSun实验和正在为橡树岭国家实验室准备的中子电偶极矩实验。 J.米勒是费米实验室Mu 2 e实验的共同领导者，该实验将寻找在不发射中微子的情况下将μ子转换为电子的方法。B.L.罗伯茨是费米实验室μ子g-2实验的共同领导者，该实验将测量与μ子相关的磁性，比布鲁克海文国家实验室先前的实验精确四倍。 这两个实验都在寻找标准模型无法解释的新物理学的证据，标准模型目前描述了粒子物理学中所有测量的量，但已知是不完整的。先前g-2实验的结果显示了一些新的线索，这应该由费米实验室的实验来澄清。该方案是对瑞士日内瓦大型强子对撞机在能源前沿的研究的补充。R.凯里正在进行MuSun实验，该实验测量负μ介子捕获氘核（由质子和中子组成）的速率，并通过将质子转化为中子来将其分解。 这个过程很有趣，因为它可能与两个质子融合在一起形成氘有关，“氢的燃烧”为太阳提供动力。