Summary:

It is now established that about 95% of the energy density of the Universe is made up of Dark Matter (DM) and Dark Energy (DE). Given our limited understanding of their physical nature, an intriguing possibility is to test interactions involving the dark components of the model. In this talk, I will focus on two different categories of interactions: scatter-like interactions between DM and neutrinos, and interacting DE. I will show that both offer interesting perspectives from a theoretical and observational standpoint. I will argue that small-scale Cosmic Microwave Background (CMB) observations can open novel observational windows to accurately test interactions, possibly revealing unique signatures that would be challenging to detect on larger angular scales. Interestingly, several independent CMB observations seem to hint at a mild preference for an interacting dark sector that might help with cosmological tensions.

For more information please contact Montandon T.