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.

这个核磁共振项目将建造一个大型的、新型的磁静电光谱仪，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-中微子关联，“b”，Fierz干扰项，以及“A/B/C”，β/中微子/质子不对称。该装置将安装在橡树岭国家实验室散裂中子源(SNS)的基本中子物理光束线(FnPB)上。拟议中的分光计将是美国和世界上精确研究中子β衰变的主要仪器(在~1000分贝的水平上)。预计这项实验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。拟议中的装置，再加上最先进的中子束，将使合作能够对某些过程设定严格的限制，这些过程将扩展标准模型，对天体物理学具有重大影响。该光谱仪将由弗吉尼亚大学(UVA)、亚利桑那州立大学(ASU)和ORNL组成的财团开发和建造，UVA是牵头机构。除了推进基础科学，拟议中的项目主要影响高等教育。弗吉尼亚大学和亚利桑那州立大学的小组已经建立了培养博士和博士后科学家的记录，这些科学家已经开始在学术界、研究和工业中扮演有成效的角色。几名本科生将在这个拟议的项目中获得宝贵的研究经验；四名学生已经深入参与了设计阶段。此外，PIs的团体有一个既定的记录，即包括代表人数不足的少数族裔的成员(最近有两名非裔美国博士生，以及女性博士生、博士后和本科生)。私人投资机构坚定地致力于吸引任职人数不足的群体成员，以帮助扩大外地的人力资源基础。

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.