A Guided-Beam Measurement of the Electron's Electric Dipole Moment

电子电偶极矩的导束测量

• 批准号: 1206042
• 负责人: John Furneaux
• 金额: $ 2.5万
• 依托单位: University of Oklahoma Norman 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: 2012-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206042&HistoricalAwards=false
• 关键词: Guided; Beam; Measurement; Electron; Electric

This grant supports the development of a Ramsey double resonance apparatus using a coherently excited molecular beam of PbF to search for the electron's electric dipole moment (e-EDM). The current phase of the work involves precise spectroscopy of the transitions and states of the PbF molecule that will be used in the e-EDM search -- the hyperfine-resolved transition between the ground state X1(nu=0,J=1/2,+,|M|=1,F=1) and the excited state A(nu=0,J=1/2,+,M=0,F=1)). Specifically, we are making precision determinations of the energy of this transition and the effect of an applied E field to this transition. The latter measurement will determine the PbF molecular electric dipole moment to higher accuracy than currently known. We are also improving the stability of our laser system by using precisely characterized absorption lines in diatomic isotopic 130-Tellurium molecule. Future steps in this project include testing our entire measurement system along with our understanding of the Geometric Phase, an important systematic error in our proposed measurement, by constructing a molecular beam with an adjustable geometric phase. We will then show that we can predict, produce and measure this geometric phase for a specific configuration of electric fields.One of the profound puzzles associated with our understanding of the universe is the asymmetry between matter and anti-matter that is observed. Why is our universe made of matter and not anti-matter? A factor that affects this asymmetry is the shape of the electron as determined by measuring the electron's electric dipole moment (e-EDM). The possibility of such an e-EDM was first proposed by Purcell and Ramsey (Phys. Rev. 78, 807 (1950)) over 60 years ago. A new limit on the e-EDM was recently reported in Nature, 473,493 (2011) by a group at Imperial College, London. We are working on a similar, more sensitive, experiment to either set an even lower limit on this important constant or to more precisely measure it using PbF. We are in the preliminary phases of the planned experiment and this grant funds important spectroscopic measurements and equipment developments making an eventual e-EDM measurement possible.

这项拨款支持拉姆齐双共振装置的发展，使用相干激发的PbF分子束来寻找电子的电偶极矩（e-EDM）。目前阶段的工作涉及将用于e-EDM搜索的PbF分子的跃迁和状态的精确光谱学--基态X1（nu=0，J=1/2，+，|M| =1，F=1）和激发态A（nu=0，J=1/2，+，M=0，F=1））。具体地说，我们正在精确地确定这种转变的能量和施加电场对这种转变的影响。后者的测量将确定PbF分子的电偶极矩比目前已知的更高的精度。我们还通过使用双原子同位素130-碲分子中精确表征的吸收线来提高我们的激光系统的稳定性。在这个项目中的未来步骤包括测试我们的整个测量系统沿着我们的理解的几何相位，在我们提出的测量中的一个重要的系统误差，通过构建一个分子束与可调的几何相位。然后我们将证明我们可以预测、产生和测量特定电场配置的几何相位。与我们对宇宙的理解相关的一个深刻的难题是观察到的物质和反物质之间的不对称性。为什么我们的宇宙是由物质而不是反物质组成的？影响这种不对称性的一个因素是通过测量电子的电偶极矩（e-EDM）确定的电子的形状。60多年前，珀塞尔和拉姆齐（Phys. Rev. 78，807（1950））首次提出了这种e-EDM的可能性。最近，伦敦帝国理工学院的一个小组在Nature，473，493（2011）中报道了e-EDM的新限制。我们正在进行一个类似的，更灵敏的实验，要么设置一个更低的限制，这个重要的常数或更精确地测量它使用PbF。我们正处于计划实验的初步阶段，这笔赠款资助了重要的光谱测量和设备开发，使最终的电子EDM测量成为可能。