Speaker: Kunio Kaneta
Freeze-In Massive Particle (FIMP) is characterized by its feeble coupling to the SM particles. Such feeble interactions still allow for FIMP dark matter to be produced by annihilations of the SM particles, whereas the backward reactions rarely occur, preventing the dark matter candidate to reach thermal equilibrium. A wide class of models may have FIMP dark matter candidate, and a well know example is gravitino. In my talk, I will argue that in some cases the produced dark matter number density is strongly affected by inflaton dynamics after the end of inflation. As an example, I will consider a case where dark matter is produced through energy-momentum portal couplings, in conjunction with Starobinsky inflation model. Then, I will extend the argument to more generic cases where inflaton undergoes anharmonic oscillation during reheating, and emphasize that the dark matter production during this period significantly alters the prediction of the dark matter relic abundance.