Asymptotic safety in the dark

TL;DR

This paper investigates the potential for asymptotic safety in a dark matter model with fermions and scalars, showing how quantum fluctuations can lead to a UV-complete theory and influence parameter constraints.

Contribution

It demonstrates that a simple fermion-scalar dark matter model can be asymptotically safe, with quantum effects stabilizing the theory at high energies.

Findings

Fermionic fluctuations lower the scalar mass bound from vacuum stability.

The model exhibits a UV fixed point through a balance of fluctuations.

Asymptotic safety constrains the portal coupling based on dark sector parameters.

Abstract

We explore the Renormalization Group flow of massive uncharged fermions -- a candidate for dark matter -- coupled to a scalar field through a Higgs portal. We find that fermionic fluctuations can lower the bound on the scalar mass that arises from vacuum stability. Further, we discuss that despite the perturbative nonrenormalizability of the model, it could be ultraviolet complete at an asymptotically safe fixed point. In our approximation, this simple model exhibits two mechanisms for asymptotic safety: a balance of fermionic and bosonic fluctuations generates a fixed point in the scalar self-interaction; asymptotic safety in the portal coupling is triggered through a balance of canonical scaling and quantum fluctuations. As a consequence of asymptotic safety in the dark sector, the low-energy value of the portal coupling could become a function of the dark fermion mass and the scalar mass, thereby reducing the viable parameter space of the model.