Limitations of Freeze-in WIMP Dark Matter from Supercooled Phase Transitions

TL;DR

This paper investigates the feasibility of producing WIMP dark matter through a freeze-in process triggered by supercooled phase transitions, finding that most minimal models do not satisfy the necessary conditions, with only one scalar model remaining viable.

Contribution

The study systematically evaluates various single-component dark matter models for freeze-in via supercooled phase transitions, identifying the scalar model as uniquely viable.

Findings

Most models do not satisfy T2 >> T1 condition for freeze-in.

Only the scalar dark matter model fulfills the necessary condition.

Constraints suggest multi-component models may be needed for successful freeze-in.

Abstract

We revisit the possibility of producing Weakly Interacting Massive Particle (WIMP) dark matter via a freeze-in mechanism triggered by a supercooled first-order phase transition (FOPT) in the early universe. Unlike traditional freeze-out and FIMP scenarios, this mechanism relies on a rapid entropy injection that dilutes the preexisting dark matter abundance and prevents re-equilibration due to a sudden mass increase. In this study, we systematically examine a variety of single-component dark matter models-including vector, fermionic, and scalar-mediated candidates-to assess whether they can satisfy the key cosmological condition T2 >> T1, required for successful WIMP freeze-in after FOPT. Contrary to earlier results, our revised analysis finds that none of the models fulfill this condition across viable parameter spaces. We confirm, however, that the scalar dark matter model analyzed in Ref. [1] is the only known viable single-component model that fulfills T2 >> T1 and enables WIMP freeze-in via this mechanism. These findings place important constraints on model-building efforts and suggest that successful freeze-in after FOPT may require multi-component or more complex dark sectors beyond the scope of minimal models.