Precision Measurements with Cold and Ultracold Neutrons

这项拨款支持用冷中子进行精确测量，以更好地理解基本粒子之间的基本相互作用。通过第一个子项目Nab光谱仪，计划对中子衰变进行精确研究。光谱仪正处于建设阶段，有了这笔资金，PI小组在磁体设计、系统研究、主电极系统、真空系统和单能质子源的建设方面的努力得到了支持。第二个子项目，npdgamma实验，旨在更好地理解弱强子相互作用。实验在散裂中子源冷中子束线FNPB处进入了数据采集阶段。这笔拨款支持PI小组对磁场环境，数据采集和数据分析的贡献。这个实验项目的共同目标是在以前无法到达的地区测试标准模型，或者至少不那么精确。标准模型中无法解释的事物的发现也将对高能物理学和宇宙学产生重要影响。该项目对高等教育产生了宝贵的影响：大部分工作是由本科生、研究生和博士后完成的，他们为未来的职业生涯获得了宝贵的技能和经验。

This grant supports precision measurements with cold neutrons that serve to better understand the fundamental interactions between elementary particles. With the first sub-project, the Nab spectrometer, a precision study of neutron beta decay is planned. The spectrometer is in the construction phase, and with this grant the PI's group's efforts in magnet design, systematic studies, the construction of the main electrode system, the vacuum system, and a monoenergetic proton source are supported. The second sub-project, the npdgamma experiment, aims to better understand weak hadronic interactions. The experiment has entered the data taking phase at the cold neutron beamline FNPB of the Spallation Neutron Source. This grant supports the PI's group's contribution to magnetic field environment, data taking and data analysis.The common goal of this experimental program is to test the Standard Model in regions which were not accessible before, or at least not as precise. A discovery of something not explained in the Standard Model would also have important implications for High Energy Physics and Cosmology. The project have a valuable impact on higher education: most of the work is done by students at undergraduate and graduate level and postdocs, who earn valuable skills and experiences for their future career.