Confronting Dark Matter Freeze-In during Reheating with Constraints from Inflation

Understand

We investigate the production of particle Dark Matter (DM) in a minimal freeze-in model considering a non-instantaneous reheating phase after inflation.

• We demonstrate that for low reheating temperatures, bosonic or fermionic reheating from monomial potentials can lead to a different evolution in the DM production and hence to distinct predictions for the parent particle lifetime and mass, constrained by long-lived particle (LLP) searches.
• We highlight that such scenario predicts parent particle decay lengths larger compared to using the instantaneous reheating approximation.
• Moreover, we demonstrate the importance of an accurate definition of the reheating temperature and emphasize its relevance for the correct interpretation of experimental constraints.