16 May 2023
Dark Matter (DM) is an elusive type of Matter that has been introduced to explain several cosmological and astrophysical observations like e.g. the cosmic microwave background power spectrum or the galactic rotation curves. Although very important on large scales, Dark Matter has not been directly detected so far, in particular with particle accelerators like the Large Hadron Collider at CERN. Motivated by the lack of detection of a new particle at energy scales of MeV-TeV, new models of very light Dark Matter have recently been developed. In these so-called ultralight dark matter models, Dark Matter is made of a light boson (whose mass is much lower than the eV). This new boson can have different properties and can have several distinct behaviors. For example, it can exhibit an oscillatory behavior (this is called oscillatory Dark Matter) or it can generate “clumps” of Dark Matter (known as topological defects) that will be moving through space-time.
Within the “Theory and Metrology” group, we are interested in the theoretical developments related to these models of Dark Matter and in the derivation of the observable signatures that they produce. This first research axis is purely theoretical and is important in order to identify the best measurements that can be used to optimize an hypothetical discovery. Amongst others, these Dark Matter candidates will interact with the fields of the standard model of particle physics and produce signature in atomic sensors. This signature is directly related to space-time variations of the constants of Nature like the masses of the fundamental particles or the fine structure constant, which is characteristic of a violation of the Einstein Equivalence Principle.
- Dual Rb/Cs atomic fountain
- Dual Rb/Cs atomic fountain operated at SYRTE and used to search for ultra light dark matter
In addition, a large part of our activity is devoted to the analysis of different measurements in order to search for these Dark Matter candidates. This part of our research is performed in close collaboration with several other groups within the SYRTE. Indeed, the SYRTE is a main actor in the development of atomic and optical clocks and has some of the best performing clocks in the world. These measurements have already been used to produce the best search (so far) for oscillating Dark Matter [1,3]. In addition, the SYRTE is a main actor in Europe in the development of fiber links to perform long distance clock comparisons between different labs in Europe (in particular with the PTB in Germany and the NPL in UK)[4]. Finally, the SYRTE has access and the knowledge to analyze satellite data like the Galileo GNSS satellite data. All these dataset can be used to search for Dark Matter candidates (see [2] for a use of GPS observations to search for dark matter) and can be combined into a worldwide network that is optimal to constrain these models of Dark Matter or to discover new physics.
Recently the DAMNED (DArk Matter from Non-Equal delays) [3] experiment using an ultra stable optical cavity and a fibre interferometer has been used for a search of Dark Matter in a hitherto mostly unexplored mass region. We did not find any DM but have improved existing constraints in several DM models by orders of magnitude. This work continues in view of experimental improvements and extensions to other types of DM.
Projects
Literature
[1] A. Hees, J. Guéna, et al, Phys. Rev. Letters 117, 061301, 2016.
[2] B. Roberts, B. Blewitt, et al, Nature Com. 8, 1195, 2017.
[3] E. Savalle, A. Hees, et al, Phys. Rev. Lett. accepted 2021.
[4] B. Roberts, P. Delva, et al, New J. of Phys., 22, 093010, 2020.