UV Freeze-in in Starobinsky Inflation

TL;DR

This paper explores how UV freeze-in mechanisms in Starobinsky inflation can produce the correct dark matter abundance across a wide mass range, influenced by effective interactions between sectors.

Contribution

It demonstrates that non-renormalizable interactions significantly broaden the dark matter mass spectrum achievable via UV freeze-in in Starobinsky inflation.

Findings

UV freeze-in can generate the correct dark matter abundance for masses from keV to PeV.

Effective interactions can enhance dark matter production without disrupting inflation dynamics.

The inflaton decay into dark matter is also affected by these interactions.

Abstract

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.