Intermediate Energy Physics at Boston University

波士顿大学中间能源物理

• 批准号: 0100468
• 负责人: James Miller
• 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: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0100468&HistoricalAwards=false
• 关键词: Intermediate; Energy; Physics; Boston; University

Our Intermediate Energy research group at Boston University consists of threefaculty, two postdoctoral fellows, four graduate students, and severalpart-time undergraduate students. In the next three years, we will:1) Continue to work on the Muon g-2 experiment. The muon is likea heavy electron but is unstable and decays like a radioactive nuclearisotope. Because it has both spin and charge, it behaves like a microscopicbar magnet, whose magnetism we measure in our experiment (g-2). Our latestvalue, based on a small part of our data, disagrees with the Standard Model(a theory which describes the particles in nature and the forces between them)prediction by several times the error. If this disagreement persists afterwe analyze all of our data, it will be very exciting since it suggests theexistence of new physics beyond the standard model. We plan two otherexperiments using the same large storage ring magnet which is used forg-2, the measurement of the muon electric dipole moment(EDM) and thedirect measurement of the muon neutrino mass. The EDM is expected intheory to be smaller than we can measure, while indirect measurementsfrom other experiments suggest that the neutrino mass is not zero.2) Measure the muon lifetime, which determines the strength of theweak interaction within the standard model.3) Measure the muon to electron conversion rate to unprecedented accuracy,a process which is forbidden by the Standard Model.All of these measurements directly test the Standard Model. Anysignificant deviation of the experimental values from theory would implythat there is physics beyond what we already know.

我们波士顿大学的中间能源研究小组由三名教师、两名博士后、四名研究生和几名兼职本科生组成。未来三年，我们将：1）继续开展Muon g-2实验。 μ子就像重电子，但不稳定并且会像放射性核同位素一样衰变。因为它同时具有自旋和电荷，所以它的行为就像一个微型条形磁铁，我们在实验中测量了它的磁性 (g-2)。我们基于一小部分数据得出的最新值与标准模型（一种描述自然界粒子及其之间力的理论）的预测不一致，误差有几倍。如果在我们分析所有数据后这种分歧仍然存在，那将非常令人兴奋，因为它表明存在超出标准模型的新物理学。我们计划使用与forg-2相同的大型存储环磁体进行另外两个实验，即μ子电偶极矩（EDM）的测量和μ子中微子质量的直接测量。理论上 EDM 预计会比我们能测量到的要小，而其他实验的间接测量表明中微子质量不为零。2）测量 μ 子寿命，它决定了标准模型中弱相互作用的强度。3）以前所未有的精度测量 μ 子到电子的转换率，这是标准模型禁止的过程。所有这些测量都直接测试标准模型。实验值与理论的任何显着偏差都意味着物理学超出了我们已知的范围。