When: Wednesday, November 22, 2023, 3:30 PM - 5:00 PMWhere: Physics (G. O. Jones building) Room 516, Mile End
Speaker: William Giarè (Sheffield)
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). Within the standard cosmological model, DM is represented by non-relativistic (or cold) massive particles that do not interact with other particles except through gravity, while DE is represented by a cosmological constant term in the Einstein equations. However, given our limited understanding of the dark components of the model, an intriguing possibility is to incorporate interactions involving DM and/or DE. In this talk, I will focus on two different categories of interactions: scatter-like interactions between DM and neutrinos, and interacting DE. I will argue that both offer interesting perspectives from a theoretical and observational standpoint. I will argue that small-scale Cosmic Microwave Background (CMB) observations recently released by ground-based telescopes can open novel observational windows to accurately test interactions, possibly revealing unique signatures that would be challenging to detect on the larger angular scales probed by the Planck satellite experiment. Interestingly, several independent CMB observations seem to hint at a mild preference for an interacting dark sector that might help with cosmological tensions.