Imprint of matter-antimatter asymmetry on collapsing domain walls

TL;DR

This paper proposes a new mechanism for biasing collapsing domain walls via radiative corrections from an asymmetric Dirac fermion, linking gravitational wave signals to early universe asymmetries and matter-antimatter imbalance.

Contribution

It introduces a novel origin of bias terms at finite temperature, expanding the parameter space for observable gravitational waves from collapsing domain walls.

Findings

New viable parameter space for collapsing domain walls.

Potential gravitational wave signals detectable at future experiments.

Implications for baryon asymmetry, dark matter, and neutrino asymmetry.

Abstract

Spontaneous breaking of discrete symmetries play non-trivial role in many well-motivated particle physics models. However, it leads to a network of cosmologically unwanted domain walls (DWs) which can be made unstable by introducing a bias term in the scalar potential. In this letter, we provide a novel origin of such bias terms at finite temperature due to radiative corrections from a Dirac fermion with large asymmetry $\sim \mathcal{O}(0.1)$ in its number density. In addition to getting a new viable region of parameter space for collapsing DWs not explored previously and resulting gravitational waves (GWs) accessible at future experiments, the viability of the scenario crucially depends on the temperature of asymmetry generation too. This provides a unique way of probing both the amount of asymmetry and the corresponding temperature via future observations of GWs from collapsing DWs. The large asymmetry in the Dirac fermion can also have interesting implications for the observed baryon asymmetry as well as dark matter and large neutrino asymmetry.