In this talk I will introduce a novel particle physics framework addressing multiple cosmological tensions, including discrepancies in the Hubble parameter, S8, and Lyman-\alpha forest data. This model, SIDR+z_t (Self-Interacting Dark Radiation with transition redshift), features an inelastic dark matter (IDM) scenario coupled with dark radiation under a dark gauge symmetry. The model...
The dynamics of cosmic reheating, that is, on how the energy stored in the inflaton is transferred to the standard model (SM) thermal bath, is largely unknown. In this work, we show that the phenomenology of the nonbaryonic dark matter (DM) ultraviolet freeze-in production strongly depends on the dynamics of the cosmic-reheating era. Using a general parametrization for the Hubble expansion...