RUI: A High Precision Measurement of the Electron-Antineutrino Correlation Coefficient in Free Neutron Decay

RUI：自由中子衰变中电子-反中微子相关系数的高精度测量

• 批准号: 0970087
• 负责人: Alexander Komives
• 金额: $ 15.97万
• 依托单位: DePauw University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0970087&HistoricalAwards=false
• 关键词: RUI; Precision; Measurement; Electron; Antineutrino

The electroweak standard model describes two of the four fundamental forces present in the universe. By conducting experiments that probe with increasing sensitivity phenomena that can be described with this model, it is hoped discrepancies will appear that will lead to a more complete understanding of the weak interaction. This interaction is responsible for the decay, or transformation, of the neutron into a proton, electron and antineutrino. By studying the correlations between the properties of the neutron and its decay products, more precise tests of the electroweak standard model can be performed. One of these correlations, known as little "a," involves the direction of emission of the electron and antineutrino from the decay region. Other neutron decay correlations are known to within 1%, but little "a" is only known to 4%. After several years of planning and construction, the aCORN ("a" CORrelation in Neutron decay) collaboration is in the process of installing an apparatus on the fundamental physics beamline at the NIST (National Institute of Standards and Technology) Center for Neutron Research (NCNR). Production data will be collected the rest of this year (2010) and into the next that will result in a 2% measurement of little "a." The NCNR will then shutdown for a series of upgrades resulting in a higher neutron flux. During this period, improvements and modifications will be made to the aCORN apparatus based on performance for the 2% measurement to make a sub-1% measurement once the NCNR upgrades are complete. This grant will provide the support needed for DePauw University undergraduate students and the Principal Investigator to participate in the experiment during the 2% measurement, to determine the necessary modifications for a sub-1% measurement and to perform this measurement. The Principal Investigator has involved 20 undergraduates extensively in this experiment over the past several years. Of these 20, 12 first encountered this experiment during their freshman year and 9 became or already were physics majors. Of these 9, 3 have participated in other research programs via the NSF's REU (Research Experience for Undergraduates) program at major research universities and facilities such as Fermilab. Five of the 9 have also had further experiences working with the PI on experiments at Los Alamos National Laboratory and the Paul Scherrer Institut in Switzerland. By working on aCORN these students have been prepared to take on a wide variety of challenges ranging from other physics experiments to activities in other diverse fields such as biology, computer science and teaching.

Electroweak标准模型描述了宇宙中存在的四个基本力中的两个。 通过进行可以用这种模型来描述的敏感性现象探测的实验，希望会出现差异，从而使人们对弱相互作用有更全面的理解。 这种相互作用是导致中子衰减或转化为质子，电子和抗肿瘤的。 通过研究中子的性质及其衰减产物之间的相关性，可以对Electroweak标准模型进行更精确的测试。 这些相关性之一，称为较小的“ a”，涉及从衰减区域中电子和抗神经抗体的发射方向。 已知其他中子衰减相关性在1％以内，但几乎没有4％的“ A”。 经过数年的计划和施工，橡子（中子衰减中的“ A”相关性）在进行NIST（国家标准技术研究所）中子研究中心（NCNR）的基本物理光束线上安装设备。 生产数据将在今年（2010年）的剩余时间内收集到下一个，这将导致小小“ a”的测量结果为2％。 然后，NCNR将关闭一系列升级，从而导致较高的中子通量。 在此期间，一旦NCNR升级完成，将根据2％测量的性能对橡子设备进行改进和修改。该赠款将为DePauw大学本科生和主要研究人员提供所需的支持，以在2％的测量过程中参与实验，以确定对低1％测量的必要修改并进行此测量。 在过去的几年中，主要研究人员在这项实验中广泛涉及20名本科生。 在这20个中，有12个在大一的一年中首次遇到了这项实验，而9个已经成为物理学专业。 在这9个中，有3个通过NSF的REU（本科生的研究经验）参加了其他研究大学和Fermilab等设施的其他研究计划。 9个中有5个也有进一步的经验与PI在洛斯阿拉莫斯国家实验室和瑞士的保罗·施雷尔学院进行实验方面。 通过在橡子上工作，这些学生已经准备好应对从其他物理实验到其他不同领域的活动，例如生物学，计算机科学和教学。