An improved measurement of the electron electric dipole moment using YbF molecules.

我们已经开发出一种方法，通过仔细研究电子在电场中的行为来测量电子的形状。我们研究的每个电子都是一个分子（氟化镱）的一部分，它可以放大外加电场，也可以作为一个锚，这样电子就不会被电场冲走。我们使用激光和射频场来准备电子在特定方向上的自旋。电场使这个自旋方向旋转的量取决于电子的形状，我们测量这个旋转角度。我们最近对电子的形状进行了最灵敏的测量，现在我们计划利用我们的方法将测量的精度提高20倍。这个原子物理实验将为描述亚原子粒子的基本物理定律提供重要的新信息。我们还希望能揭示物理学中最大的谜团之一：为什么宇宙中的物质比反物质多得多？目前最好的粒子物理学理论——标准模型——以惊人的准确度预测了亚原子粒子的行为，但显然它是不完整的。例如，它不包括引力的影响，它不能解释为什么不同的自然力有如此大的不同强度，它不能重现观察到的物质/反物质的不对称性。物理学家提出了许多扩展标准模型的想法，但我们不知道这些提出的理论中，如果有的话，哪个是正确的。我们对电子形状的测量可以帮助解决这个问题，因为不同的理论预测了不同的形状。通过提高测量的准确性，我们可以检验这些理论。最受欢迎的理论之一被称为超对称。我们最近的测量已经排除了这个理论的一些版本。随着计划中的改进，我们的新测量要么将排除大多数版本的超对称，要么将提供一些证据证明超对称是正确的。物理学家认为，宇宙始于大爆炸，大爆炸应该创造了等量的物质和反物质，然而今天我们只能看到少量的反物质，它们来自宇宙射线和放射性衰变等不寻常的东西。这是一个谜，因为它暗示了标准模型中不存在的物质和反物质规律之间的不对称性。我们的测量是相关的，因为电子的形状对这种不对称非常敏感。即使是微小的差异也会显著扭曲形状，所以我们的测量可能有助于解开早期宇宙演化的谜团。

We have developed a method to measure the shape of the electron by carefully studying how it behaves when it is placed in an electric field. Each electron that we study is part of a molecule (ytterbium fluoride), which amplifies the applied electric field and also serves as an anchor so that the electron is not swept away by the field. We use lasers and radiofrequency fields to prepare the electron's spin in a particular direction. The electric field causes this spin direction to rotate by an amount that depends on the electron's shape, and we measure this angle of rotation. We have recently made the most sensitive measurement of the electron's shape and we now plan to exploit our method to improve the precision of the measurement by a factor of 20.This atomic physics experiment will provide important new information about the fundamental laws of physics that describe sub-atomic particles. We also hope to shed some light on one of the biggest mysteries in physics: why there is so much more matter than antimatter in the universe.The best theory of particle physics at the moment, the Standard Model, predicts the behaviour of sub-atomic particles with amazing accuracy, but it is obviously incomplete. For instance, it doesn't include the effects of gravity, it can't explain why the different forces of nature have such widely differing strengths, and it can't reproduce the observed matter/antimatter asymmetry. Physicists have proposed many ideas to extend the Standard Model, but we don't know which, if any, of these proposed theories is the right one.Our measurement of the electron's shape can help sort this out, because the different proposed theories predict different shapes. By increasing the accuracy of our measurement, we can test these theories. One of the favourite theoretical ideas is called supersymmetry. Our recent measurement has already ruled out some versions of this theory. With the planned improvement, our new measurement will either rule out most versions of supersymmetry, or will provide some evidence that supersymmetry is correct.Physicists think that the universe started with the big bang, which should have created equal amounts of matter and antimatter, yet today we only see tiny amounts of antimatter, coming from unusual things like cosmic rays and radioactive decay. This is a puzzle because it implies an asymmetry between the laws governing matter and antimatter that is not in the Standard Model. Our measurement is relevant because the shape of the electron is extremely sensitive to such an asymmetry. Even a tiny difference would distort the shape significantly, so our measurement may help to solve this mystery about the evolution of the early universe.