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.

对基本粒子性质的精确实验测试现在是一种行之有效的方法，可以在我们现有的物理知识之外寻找新的自然定律。 拟议的研究是两个实验，以精确测量一种称为μ子的基本粒子，它与电子相似，但质量更大。 费米国家加速器实验室的一个实验，称为g-2，将测量μ子的磁矩，精度超过百万分之一，这将提供粒子物理学标准模型的测试，该理论解释了构成宇宙中大部分可见物质的基本粒子的性质。 另一个实验名为MuSun，位于瑞士的Paul Scherrer研究所（PSI），将测量由一个μ子和一个氘核（由一个质子和一个中子组成的原子核）组成的原子的寿命。 该实验将进一步了解为太阳提供动力的热核氢燃烧反应，并有助于了解中微子与物质的相互作用。μ介子g-2实验将测量μ介子的异常磁矩为140 parts per-billion，比布鲁克海文国家实验室（BNL）先前的实验E821提高了四倍。测量将解决E821和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一个关键测试，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到费米实验室，以及新的探测器、电子设备和采集系统。 PI和他的团队负责8 GByte/sec的热量计读数，使用基于多万亿次GPU的数据处理，以及数据采集系统的分布式事件构建。 MuSun实验将测量mu- d到n n中微子双态捕获率，精度为1.5%。 该测量解决了早期测量mu d捕获量之间长期存在的差异。 它将使我们对在pp热核聚变中起作用的两体弱轴向电流、中微子实验的截面以及普通和双β衰变的知识有五倍的提高。