UV Freeze-in in Starobinsky Inflation

Understand

In the Starobinsky model of inflation, the observed dark matter abundance can be produced from the direct decay of the inflaton field only in a very narrow spectrum of close-to-conformal scalar fields and spinors of mass $\sim 10^7$ GeV.

• This spectrum can be, however, significantly broadened in the presence of effective non-renormalizable interactions between the dark and the visible sectors.
• In particular, we show that UV freeze-in can efficiently generate the right dark matter abundance for a large range of masses spanning from the keV to the PeV scale and arbitrary spin, without significantly altering the heating dynamics.
• We also consider the contribution of effective interactions to the inflaton decay into dark matter.