Signatures of Dark Matter: molecular detectors of oscillating fundamental constants

尽管暗物质(DM)在宇宙中比正常物质丰富得多，但它还没有在实验室实验中被毫无疑问地检测到。该项目旨在开发一种对某些暗物质信号敏感的实验。暗物质可能部分由低质量的粒子组成(在nev/c^2的范围内)。它可以表现为一个以康普顿频率振荡的场，耦合到标准模型(SM)场。这将导致基本常数的振荡，例如精细结构常数、夸克质量、强力的耦合常数。在这个项目中，我们考虑分子中的振动跃迁。它们对电子质量、核质量和精细结构常数都很敏感。通过核质量，也依赖于夸克质量和强力的耦合常数。将要开发的设备将用于搜索室温分子气体中振动跃迁频率的振荡。为此，将使用1.5微米乙炔(C2H2)的激光光谱分析。光学谐振器的谐振频率将被用作参考频率。这项实验将在几个方面进行优化。将研究非常大的康普顿频率范围(10赫兹-100兆赫)，将使用两种光谱变体，将达到灵敏度的散粒噪声水平，分子跃迁被有利地选择，相关技术将允许抑制干扰，并且实验将在长达一年的测量时间内记录大量数据。在项目结束时，我们希望将DM场与SM场的耦合强度上限降低100到1000倍。

Although dark matter (DM) is much more abundant in the universe than normal matter, it has not yet been detected beyond doubt in laboratory experiments. This project aims to develop an experiment that will be sensitive to certain dark matter signatures. Dark matter could consist partly of particles of low mass (in the range neV/c^2). It could behave as a field oscillating at the Compton frequency, coupling to the Standard Model (SM) fields. This would result in oscillating fundamental constants, e.g. the fine structure constant, the quark masses, the coupling constant of the strong force. In this project we consider vibrational transitions in molecules. These are sensitive to the electron mass, the nuclear mass, and the fine structure constant. Via the nuclear mass, there is also a dependence on the quark masses and the coupling constant of the strong force. The apparatus to be developed will be used to search for oscillations in the frequency of vibrational transitions in a room-temperature molecular gas. Laser spectroscopy at 1.5 µm of acetylene (C2H2) will be used for this purpose. The resonance frequency of an optical resonator will be used as a reference frequency. The experiment will be optimised in several respects. A very large Compton frequency range will be investigated (10 Hz - 100 MHz), two spectroscopy variants will be used, the shot noise level of sensitivity will be achieved, the molecular transition is advantageously chosen, a correlation technique will allow the suppression of interferences, and the experiment will record extensive data over up to 1 year of measurement time. At the end of the project, we expect to achieve a reduction of the upper limits for the coupling strength of a DM field to the fields of the SM by factors between 100 and 1000.