Precision Muon Experiments

精密介子实验

• 批准号: 1503552
• 负责人: Tim Gorringe
• 金额: $ 55.5万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1503552&HistoricalAwards=false
• 关键词: Precision; Muon; Experiments

Precise experimental tests of fundamental particle properties are now a well-established way to search for new laws of nature beyond our current physical knowledge. The proposed research is for two experiments to make precise measurements of an elementary particle called the muon, which is similar to the electron but with larger mass. One experiment at tha Fermi National Accelerator Laboratory, called g-2, will measure the magnetic moment of the muon to an accuracy of better than a part-per-million, which will provide a test of the Standard Model of particle physics, the theory that explains the properties of the elementary particles making up most of the visible matter in the Universe. The other experiment, called MuSun, at the Paul Scherrer Institute (PSI) in Switzerland will measure the lifetime of an atom comprised of a muon and a deuteron (a nucleus made from one proton and one neutron). This experiment will further the knowledge of the reaction of thermonuclear hydrogen burning which powers the sun, as well as helping to understand neutrino interactions with matter.The muon g-2 experiment will measure the muon anomalous magnetic moment to 140 parts-per-billion, a four-fold improvement over the previous experiment at Brookhaven National Laboratory (BNL), known as E821. The measurement will address the longstanding 3 standard deviation discrepancy between the same measurement from E821 and the Standard Model prediction. It represents a key test of the Standard Model and has broad sensitivity to new particles and interactions beyond the Standard Model. The muon g-2 project has involved the relocation of the muon storage ring from Brookhaven National Laboratory to Fermilab as well as new detector, electronics and acquisition systems. The PI and his group are responsible for the 8 GByte/sec calorimeter readout, using multi-teraflop GPU-based data processing, and distributed event building for the data acquisition system. The MuSun experiment will measure the mu- d to n n neutrino doublet capture rate to an accuracy of 1.5%. The measurement addresses a longstanding discrepancy among earlier measurements of mu d capture. It will provide a five-fold improvement in our knowledge of the two-body weak axial currents that plays a role in pp thermonuclear fusion, cross sections for neutrino experiments, and ordinary and double beta-decay.

对基本粒子特性的精确实验测试现在已成为寻找超出我们当前物理知识的新自然定律的行之有效的方法。 拟议的研究是通过两个实验来精确测量一种称为μ子的基本粒子，这种粒子与电子类似，但质量更大。 费米国家加速器实验室的一项名为 g-2 的实验将以高于百万分之一的精度测量 μ 子的磁矩，这将为粒子物理标准模型提供测试，该理论解释了构成宇宙中大部分可见物质的基本粒子的特性。 另一项名为 MuSun 的实验在瑞士保罗谢勒研究所 (PSI) 进行，将测量由 μ 子和氘核（由一个质子和一个中子组成的原子核）组成的原子的寿命。 该实验将进一步加深对为太阳提供动力的热核氢燃烧反应的了解，并帮助了解中微子与物质的相互作用。μ子 g-2 实验将测量μ子反常磁矩至十亿分之 140，比布鲁克海文国家实验室 (BNL) 之前的实验（称为 E821）提高了四倍。该测量将解决 E821 的相同测量与标准模型预测之间长期存在的 3 个标准差差异。它代表了标准模型的关键测试，并且对标准模型之外的新粒子和相互作用具有广泛的敏感性。 μ 子 g-2 项目涉及将 μ 子存储环从布鲁克海文国家实验室搬迁至费米实验室，以及新的探测器、电子设备和采集系统。 PI 和他的团队负责使用基于多兆浮点 GPU 的数据处理以及数据采集系统的分布式事件构建来实现 8 GB/秒量热计读数。 MuSun 实验将测量 mu- d 至 n n 中微子双线态捕获率，精度为 1.5%。 该测量解决了早期泥浆捕获测量之间长期存在的差异。 它将使我们对在 pp 热核聚变、中微子实验横截面以及普通和双 β 衰变中发挥作用的二体弱轴流的了解提高五倍。