# WIMP miracle of the second kind

## TL;DR

This paper explores a scale-invariant hidden sector interacting via a Higgs portal, leading to a new 'WIMP miracle' where dark matter abundance results from hidden sector freeze-out, with predictive models for scalar, fermion, or vector dark matter.

## Contribution

It introduces the concept of a 'WIMP miracle of the second kind' in scale-invariant hidden sectors, providing detailed analysis of dark matter production across different particle types.

## Key findings

- Dark matter can originate from hidden sector freeze-out due to scale invariance.
- The models predict specific observational signatures for scalar, fermion, and vector dark matter.
- Scale invariance constrains hidden sector parameters, enhancing predictive power.

## Abstract

We study dark matter production in scenarios where a scale invariant hidden sector interacts with the Standard Model degrees of freedom via a Higgs portal $\lambda \Phi^\dagger\Phi s^2$. If the hidden sector is very weakly coupled to the SM but exhibits strong interactions within its own particle species, the dark matter abundance may arise as a result of a dark freeze-out occurring in the hidden sector. Because of scale invariance, the free parameters in the hidden sector are determined and the dark matter candidate exhibits a 'WIMP miracle of the second kind'. Demonstrating the predictive power of scale invariance, we carry out thorough analysis of dark matter production in several benchmark scenarios where the hidden sector contains either a scalar, fermion (sterile neutrino), or vector dark matter, and discuss the observational consequences of these scenarios.