重原子极性分子的有效Stark减速与冷却及其eEDM精密测量

It is well known that the precision measurement of eEDM is an important breakthrough point to look for new physics beyond the standard model. In this project, we will generate a high flux diffuse PbF beam by using buffer-gas cooling technique, and using molecular internal-state interferometer to realize precision measurement of eEDM, and hope to obtain a measurement upper limitation of 1*10-26e.cm, even get into 10-27e.cm . On the other hand, because the conventional electrostatic Stark decelerator has no a better transverse guide function, its slowing efficiency is lower. In particular, when the slowing stage number is far larger than 100, or the final velocity of the slowed packet is lower than 10m/s, the conventional Stark decelerator cannot be used to realize effectively slowing and cooling of heavy-atom polar molecules. We propose a novel efficient electrostatic Stark decelerator with 2D electrostatic guiding technique. This scheme has not only some advantages of the conventional Stark decelerator, such as a simple manipulation and control modes as well as external electric devices, but also has an advantage of traveling-wave decelerator with the highest slowing efficiency, which is a most advanced and most complex decelerator in the world at present. Taking PbF as an example, we will experimental demonstrate the above new scheme, and obtain a slow and cold PbF beam with a final velocity and its width of 3-5m/s and a temperature of 50-150mK, and using this cold PbF beam to do precision measurement of eEDM, which will lay the ground-work for further rising sensitivity of eEDM measurement. We hope first realize the precision measurement of eEDM with PbF molecules, and realize efficiently slowing and cooling of supersonic or subsonic PbF beam, and obtain some important new even original results, and some results will arrive at international advanced level.

众所周知，电子EDM的精密测量是寻找标准模型以外新物理的重要突破口。本项目将采用Buffer-gas冷却技术获得高通量的射流PbF冷分子束，并采用分子内态干涉仪实现eEDM的精密测量，可望获得1*10-26e.cm 甚至进入10-27的测量上限。此外，由于传统静电Stark减速器缺乏良好的横向导引功能，因而无法胜任重原子极性分子束的有效减速与冷却。我们将提出一种采用静电导引技术的新颖高效静电Stark减速方案，并以PbF分子为例，首次实验验证上述新方案，获得末速度及其速度分布宽度为3-5m/s、温度约为50-150mK的慢速冷PbF分子束，并用于eEDM的精密测量，为进一步提高测量灵敏度奠定实验基础。可望在国际上首先采用PbF分子实现eEDM测量，实现超声或亚声速PbF分子束的有效减速与冷却，取得若干重要的创新性甚至原创性成果，部分成果达到国际先进水平。

在本重点基金项目的资助下，我们先后研制了“新颖高效静电Stark减速系统”、“PbF分子制备与缓冲气体冷却的真空实验系统”和“采用PbF冷分子实现eEDM精密测量的分子内态干涉仪实验系统”，开展了（1）新颖高效静电Stark减速器的实验验证；（2）PbF分子制备与缓冲气体冷却的实验研究；（3）全光学PbF分子内态干涉仪新原理的理论研究；（4）采用PbF冷分子实现eEDM精密测量的分子内态干涉仪实验系统的设计与研制；（5）其它有关eEDM精密测量的理论与实验研究等，并完成了PbF分子内态干涉信号的光谱探测系统的设计与研制，提出了一种高灵敏测量冷分子干涉信号的准连续共振增强多光子电离(pc-REMPI)光谱测量新方法，并开展了相应的准连续脉冲激光系统的设计与研制，可望比LIF光谱探测技术的灵敏度提高1-2个数量级，取得了一些重要的理论与实验研究进展。在国内外发表学术论文46篇，其中SCI学术论文35篇，而SCI-IF  3.0的论文20篇。