Tittel: Atomic dark matter with a massive mediator

Veileder: Felix Kahlhoefer, Michael Kachelriess

Sammendrag: In this master thesis, atomic dark matter with a massive mediator is explored. First cosmology is treated, and the ionization-fraction coming from freeze-out of dark atoms is computed. For dark photon and dark fermion masses in the MeV range, the abundance of dark ions after recombination is found to vary several orders of magnitudes with variation of parameters like the fermion masses and the dark fine structure constant. Then constraints coming from direct detection of dark atoms is treated. These constraints are found, depending on dark photon and dark fermion masses, to cut away a sizable part of the parameter space. The focus of this thesis is regions of parameter space giving an ionization fraction of $\lesssim 1%,$, which limits the constraints from cosmology, and leaves us with a constrained but not squeezed parameter space.