Fundamental symmetry tests using low energy neutrons

使用低能中子进行基本对称性测试

• 批准号: 0855584
• 负责人: Christopher Crawford
• 金额: $ 30万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0855584&HistoricalAwards=false
• 关键词: Fundamental; symmetry; tests; using; low

This award will support the study of spatial and temporal symmetries in the interactions of low energy neutrons. It seeks to answer the following questions: a) Why is our universe made up of matter but not anti-matter? b) What is the interplay between forces that bind the nucleus? The first question will be addressed by measuring the separation of electric charge in the neutron, a quantity that would change if time ran backwards. It involves the same violation of symmetry necessary to convert antimatter into matter or vice versa. Our contribution is to efficiently guide polarized neutrons thirty meters from the source into the experimental apparatus. The second question explores the forces involved in the capture of neutrons on protons to form deuterium. Even though the strong force dominates by seven orders of magnitude, the weak force would be responsible for an asymmetric distribution in the production of gamma rays, which we seek to measure. This asymmetry distinguishes our universe from a mirror reflection, one with directions in space reversed. These experiments will help unravel our understanding the interactions and structure of protons and neutrons.These projects will have significant effect on undergraduate and graduate students at the University of Kentucky, especially women, minorities, and students from the Appalachian region. These students have the opportunity of participating in cutting-edge research at Los Alamos National Laboratory (LANL) and Oak Ridge National Laboratory (ORNL). The PI is incorporating portions of this work into a course on modern physics, and is developing an introduction to scientific programming for students involved in the analysis of these experiments. General purpose software libraries developed for this research will be made publicly available. The work on neutron guides will benefit subsequent experiments at the Spallation Neutron Source at ORNL.

该奖项将支持低能中子相互作用中空间和时间对称性的研究。它试图回答以下问题：a)为什么我们的宇宙是由物质而不是反物质组成的？B)束缚原子核的力之间有什么相互作用？第一个问题将通过测量中子中电荷的分离来解决，如果时间倒退，这个量就会改变。它涉及到将反物质转化为物质所必需的对称性破坏，反之亦然。我们的贡献是有效地将极化中子从源30米处引导到实验装置中。第二个问题是探索在质子上俘获中子以形成氢的作用力。尽管强力以七个数量级为主，但弱力将导致伽马射线产生的不对称分布，这是我们试图测量的。这种不对称性将我们的宇宙与镜面反射区分开来，镜面反射的空间方向相反。这些实验将有助于我们了解质子和中子的相互作用和结构。这些项目将对肯塔基大学的本科生和研究生，特别是女性、少数民族和来自阿巴拉契亚地区的学生产生重大影响。这些学生有机会参与洛斯阿拉莫斯国家实验室(LANL)和橡树岭国家实验室(ORNL)的尖端研究。PI正在将这项工作的部分内容纳入一门现代物理课程，并正在为参与这些实验分析的学生开发一门科学编程入门。为这项研究开发的通用软件库将向公众开放。关于中子导轨的工作将有助于ORNL散裂中子源的后续实验。