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.

现在，对基本粒子性质进行精确的实验测试是一种成熟的方法，可以在我们目前的物理知识之外寻找新的自然规律。这项拟议的研究是为了进行两项实验，以精确测量一种名为Muon的基本粒子，这种粒子类似于电子，但质量更大。费米国家加速器实验室的一项名为g-2的实验将测量介子的磁矩，其精度将超过百万分之一，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多数可见物质的基本粒子的性质。另一项名为MuSun的实验是在瑞士保罗·谢勒研究所(PSI)进行的，它将测量由一个µ子和一个氘(一个质子和一个中子组成的原子核)组成的原子的寿命。这项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，并有助于了解中微子与物质的相互作用。Muon g-2实验将测量到Muon的反常磁矩为140 ppb，比布鲁克海文国家实验室(BNL)的前一次实验E821改进了四倍。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个标准偏差。它代表了标准模型的一项关键测试，并对标准模型以外的新粒子和相互作用具有广泛的敏感性。Muon g-2项目包括将Muon存储环从布鲁克海文国家实验室转移到费米实验室，以及新的探测器、电子设备和获取系统。PI和他的团队负责8 Gbyte/s量热计读数，使用基于多万亿次浮点GPU的数据处理，并为数据采集系统构建分布式事件。MuSun实验将测量mud到nn中微子对俘获率，精确度为1.5%。该测量解决了早期测量Mod捕获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电流、中微子实验的截面以及普通和双β衰变的知识提高五倍。