Ultracold EEDM - Measuring The Electron's Electric Dipole Moment Using Ultracold Molecules

超冷 EEDM - 使用超冷分子测量电子的电偶极矩

• 批准号: EP/X030180/1
• 负责人: Michael Tarbutt
• 金额: $ 239.12万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX030180%2F1
• 关键词: Ultracold; EEDM; Measuring; Electron; Electric

Our understanding of the fundamental particles, forces and symmetries of nature is far from complete. Our best theory of particle physics - the Standard Model - explains the particles and forces observed in experiments, yet fails to explain many cosmological observations about the Universe. We have little understanding of dark matter or dark energy, and no explanation for the observed asymmetry between matter and antimatter. Many theories have been constructed to address these shortcomings, but none are yet supported by experimental evidence. We aim to shed light on these important problems in particle physics and cosmology by measuring the roundness of electrons with exquisite precision.The roundness of a particle is quantified by its electric dipole moment (EDM). A non-zero EDM violates time-reversal symmetry, implying that nature has an arrow of time at a fundamental level. In almost all theories, this symmetry needs to be violated to explain the preponderance of matter over anti-matter in the Universe. In the Standard Model, the predicted value of the electron EDM is extremely tiny, whereas most new theories, including most forms of supersymmetry, predict values many orders of magnitude larger. Furthermore, some theories of dark matter predict EDMs that oscillate with a magnitude and timescale that can be measured. Thus, EDM measurements offer extraordinary potential for new discoveries - they tell us about the fundamental symmetries essential to understanding the origins and nature of our Universe, they distinguish decisively between the Standard Model and its extensions, and they offer clues about the nature of dark matter.We have built an instrument that measures the electron EDM using electrons in heavy molecules. The molecules are spin-polarized and the spin precession rate in an electric field is measured to determine the EDM. We cool the molecules to a few microkelvin so that we can watch the spin precess for a long time. This makes the measurement far more precise and is the key advance over previous measurements. The goals of the project are to bring the instrument to full sensitivity, study and control systematic effects that could give false results, then determine the electron roundness at least ten times better than ever before. We will also build the upgrades needed for a further factor of ten improvement. Our result will be sensitive to new particles with masses beyond the reach of the greatest colliders, and to interactions that orchestrated the matter-antimatter asymmetry in the Universe.

我们对自然的基本粒子、力和对称性的理解还远未完成。我们最好的粒子物理理论 - 标准模型 - 解释了实验中观察到的粒子和力，但无法解释许多关于宇宙的宇宙学观察。我们对暗物质或暗能量知之甚少，也无法解释观察到的物质与反物质之间的不对称性。人们已经构建了许多理论来解决这些缺点，但尚未得到实验证据的支持。我们的目标是通过精确测量电子的圆度来阐明粒子物理学和宇宙学中的这些重要问题。粒子的圆度是通过其电偶极矩 (EDM) 来量化的。非零 EDM 违反了时间反转对称性，这意味着自然界在基本层面上存在时间箭头。在几乎所有理论中，都需要打破这种对称性才能解释宇宙中物质相对反物质的优势。在标准模型中，电子 EDM 的预测值非常小，而大多数新理论，包括大多数形式的超对称性，预测值要大许多数量级。此外，一些暗物质理论预测 EDM 的振荡幅度和时间尺度是可以测量的。因此，EDM 测量为新发现提供了非凡的潜力 - 它们告诉我们对于理解宇宙的起源和本质至关重要的基本对称性，它们明确地区分了标准模型及其扩展，并且提供了有关暗物质本质的线索.我们建造了一种使用重分子中的电子来测量电子 EDM 的仪器。分子被自旋极化，并测量电场中的自旋进动速率以确定 EDM。我们将分子冷却到几微开尔文，以便我们可以长时间观察自旋过程。这使得测量更加精确，是比以前测量的关键进步。该项目的目标是使仪器达到最高灵敏度，研究和控制可能给出错误结果的系统效应，然后确定电子圆度，比以前至少好十倍。我们还将构建进一步改进十倍所需的升级。我们的结果将对质量超出最大对撞机范围的新粒子以及精心策划宇宙中物质与反物质不对称性的相互作用敏感。