MRI Consortium: Development of a Magneto-Electrostatic Spectrometer for High Precision Measurements of Neutron Beta Decay

MRI 联盟：开发用于高精度测量中子 β 衰变的磁静电谱仪

• 批准号: 1126683
• 负责人: Dinko Pocanic
• 金额: $ 175.21万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1126683&HistoricalAwards=false
• 关键词: MRI; Consortium; Development; Magneto; Electrostatic

This MRI project will build a large, novel magneto-electrostatic spectrometer, highly optimized for precision measurements of four key parameters describing neutron beta decay: "a", the electron-neutrino correlation, "b", the Fierz interference term, as well as "A/B/C", the beta/neutrino/proton asymmetries. The device will be mounted at the Fundamental Neutron Physics Beamline (FnPB) of the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). The proposed spectrometer will be a premier instrument for precision study (at the level of a part in ~1000) of neutron beta decay in the US and in the world. The experiment is expected to provide critical results toward resolving longstanding discrepancies in the neutron decay world data set. The proposed device, coupled with state of the art neutron beam, will enable the collaboration to set stringent limits on certain processes that would extend the Standard Model, with strong implications in astrophysics. The spectrometer will be developed and built by a consortium comprising University of Virginia (UVa), Arizona State University (ASU), and ORNL, with UVa as the lead institution.Besides advancing fundamental science, the proposed project's impact is mainly in higher education. The UVa and the ASU groups have established records of training Ph.D. and postdoctoral scientists who have proceeded to assume productive roles in academia, research, and industry. Several undergraduate students will gain valuable research experience working on the proposed project; four have already been deeply involved in the design phase. As well, the PIs' groups have an established record of including members of underrepresented minorities (in recent past there have been two African American Ph.D. students, as well as women Ph.D. students, postdocs, and undergraduate students). The PIs are strongly committed to attracting members of underrepresented groups, to help broaden the human resource base of the field.

该 MRI 项目将建造一台大型新型磁静电谱仪，高度优化用于精确测量描述中子 β 衰变的四个关键参数：“a”，电子中微子相关性，“b”，菲尔兹干涉项，以及“A/B/C”，β/中微子/质子不对称性。 该设备将安装在橡树岭国家实验室 (ORNL) 散裂中子源 (SNS) 的基础中子物理束线 (FnPB) 上。 拟议的光谱仪将成为美国和世界范围内对中子 β 衰变进行精密研究（约 1000 分之一的水平）的首要仪器。 该实验预计将为解决中子衰变世界数据集中长期存在的差异提供关键结果。 拟议的设备与最先进的中子束相结合，将使合作能够对某些扩展标准模型的过程设​​定严格的限制，对天体物理学产生重大影响。 该光谱仪将由弗吉尼亚大学 (UVa)、亚利桑那州立大学 (ASU) 和 ORNL 组成的联合体开发和建造，其中 UVa 为牵头机构。除了推进基础科学之外，拟议项目的影响主要在于高等教育。 弗吉尼亚大学和亚利桑那州立大学小组已建立了培养博士的记录。以及在学术界、研究界和工业界发挥重要作用的博士后科学家。 一些本科生将在拟议项目中获得宝贵的研究经验；其中四人已深入参与设计阶段。 此外，PI 小组也有包括代表性不足的少数族裔成员的记录（最近有两名非洲裔美国博士生，以及女博士生、博士后和本科生）。 PI 坚定致力于吸引代表性不足群体的成员，以帮助扩大该领域的人力资源基础。

项目成果

The Nab experiment: A precision measurement of unpolarized neutron beta decay

Nab 实验：非极化中子 β 衰变的精确测量

• DOI: 10.1051/epjconf/201921904002
• 发表时间: 2019
• 期刊: EPJ Web of Conferences
• 作者: Fry, J.;Alarcon, R.;Baeßler, S.;Balascuta, S.;Palos, L. Barrón;Bailey, T.;Bass, K.;Birge, N.;Blose, A.;Borissenko, D.
• 通讯作者: Borissenko, D.