On UltraViolet Freeze-in Dark Matter during Reheating

Understand

The absence of any confirmative signals from extensive DM searching motivates us to go beyond the conventional WIMPs scenario.

• The feebly interacting massive particles (FIMPs) paradigm provides a good alternative which, despite of its feebly interaction with the thermal particles, still could correctly produce relic abundance without conventional DM signals.
• The Infrared-FIMP based on the renormalizable operators is usually suffering the very tiny coupling drawback, which can be overcome in the UltraViolet-FIMP scenario based on high dimensional effective operators.
• However, it is sensitive to the history of the very early Universe.