Measurement of the neutron lifetime using a hybrid magnetic trap for ultra-cold neutrons

使用超冷中子混合磁阱测量中子寿命

• 批准号: 167643917
• 负责人: Professor Dr. Oliver Zimmer
• 金额: --
• 依托单位: Institut Laue-Langevin (ILL)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/167643917?language=en
• 关键词: Measurement; neutron; lifetime; using; hybrid

The neutron lifetime τn is a basic observable that not only determines the light-element abundances in big-bang nucleosynthesis but is also a key ingredient for understanding weak interactions within the framework of the Standard Model of particle physics. In this respect the neutron lifetime is the most important complement to the angular correlations which are the scope of the new instrument PERC. A recent experiment with quoted uncertainty of only 0.8 seconds has generated a confusing situation: its result for τn deviates from the previous world average by more than seven seconds. Since most precise past experiments employed storage of ultra-cold neutrons (UCN) in material bottles, the discrepancy calls for an approach with different systematic. Our goal is thus to measure τn within this funding period with accuracy well below 1 s, using a novel method with live detection of electrons from neutron decay within a magneto-gravitational UCN trap, coupled to a new high-density UCN source.

中子寿命τn是一个基本的可观测值，它不仅决定了大爆炸核合成中轻元素的丰度，而且也是理解粒子物理标准模型框架内弱相互作用的关键因素。在这方面，中子寿命是角相关性的最重要补充，角相关性是新仪器PERC的范围。最近的一项实验引用的不确定性只有0.8秒，却产生了一个令人困惑的情况：其τn的结果与之前的世界平均值相差7秒多。由于过去大多数精确的实验都是将超冷中子（UCN）储存在材料瓶中，因此这种差异需要一种不同系统的方法。因此，我们的目标是在此资助期内以远低于1s的精度测量τn，使用一种新颖的方法，在磁引力UCN陷阱中实时探测中子衰变中的电子，并与新的高密度UCN源耦合。