Gravitational Production of a Conformal Dark Sector

Understand

Dark sectors with purely gravitational couplings to the Standard Model are unavoidably populated from the SM plasma by graviton exchange, and naturally provide DM candidates.

• We examine the production in the relativistic regime where the dark sector is approximately scale invariant, providing general analytical formulas that depend solely on the central charge of the dark sector.
• We then assess the relevance of interactions that can lead to a variety of phenomena including thermalisation, nonperturbative mass gaps, out-of-equilibrium phase transitions and cannibalism in the dark sector.
• As an illustrative example we consider the dark glueball scenario in this light and show it to be a viable DM candidate due to the suppression of gravitational production.