Dynamic Freeze-In: Impact of Thermal Masses and Cosmological Phase Transitions on Dark Matter Production

Understand

The cosmological abundance of dark matter can be significantly influenced by the temperature dependence of particle masses and vacuum expectation values.

• We illustrate this point in three simple freeze-in models.
• The first one, which we call kinematically induced freeze-in, is based on the observation that the effective mass of a scalar temporarily becomes very small as the scalar potential undergoes a second order phase transition.
• This opens dark matter production channels that are otherwise forbidden.