Abstract: |
The early Universe was filled with a hot bath of Standard Model, and maybe also dark sector, particles. A medium of dark sector particles could have impacted the cosmic history of dark matter or dark radiation, by endowing these states with a medium-dependent mass or chemical potential. In the first part of the talk, I will discuss how a bath of millicharged particles could have impacted oscillations between dark photons and ordinary photons, by generating a thermal mass for the dark photon. These oscillations can lead to .... |