Interacting Dark Sectors and Cosmological Tensions

Speaker: Gustavo Marques Tavares

Date: Monday, March 3, 2025

Time: 4:00 – 5:00 pm

Location: 472 Willamette Hall (IFS Seminar Room)

Abstract: In this talk I will discuss the non-trivial cosmological consequences of interacting dark sectors, in which a dark radiation component has interactions with a sub-component of dark matter. I will show how the presence of extra energy density in dark radiation combined with the change in gravitational potentials due to the interactions of dark radiation with part of dark matter allows for a much larger Neff. Thus, this model can achieve a much larger value for the current expansion rate of the universe, H_0, and significantly alleviate the tension between cosmological and more direct measurements of H_0. Unlike many alternative proposals, our model achieves this without exacerbating tensions with structure formation constraints at smaller scales. I will present specific signatures of these dark matter-dark radiation interactions in the matter power spectrum that could be detected by current surveys such as DESI, providing a promising path to testing this solution observationally.

Host: Pouya Asadi