Relics

Abstract

After we understand the relic photons in the Universe, we can focus on a set of different other relics, including the first dark matter candidates. For those the main question is to explain the observed value of Ω _χ h ² ≈ 0.12. Before we will eventually turn to thermal production of massive dark matter particles, we can use a similar approach as for the photons for relic neutrinos. Furthermore, we will look at ways to produce dark matter during the thermal history of the Universe, without relying on the thermal bath.