Baryogenesis via the Chiral Magnetic Effect in a First-Order Electroweak Phase Transition

TL;DR

This paper explores how the chiral magnetic effect during a first-order electroweak phase transition can amplify lepton asymmetry and contribute to baryogenesis, highlighting the importance of primordial magnetic fields and specific model parameters.

Contribution

It demonstrates that the chiral magnetic effect can significantly enhance baryon asymmetry generation during the electroweak phase transition, which was previously underestimated.

Findings

Chiral magnetic effect amplifies lepton asymmetry during phase transition.

Helical magnetic fields alone cannot produce sufficient baryon asymmetry.

Parameter space constraints for phase transition and magnetic fields are identified.

Abstract

In this paper, we investigate the generation of the baryon asymmetry of the universe during the first-order electroweak phase transition. We first study the generation of the helical magnetic field in the framework of the standard model effective field theory with a CP-violating operator. We show that, when the chiral magnetic effect is absent, the helical magnetic field and effective chemical potential cannot generate enough baryon asymmetry when vacuum bubbles collide. We further find that the chiral magnetic effect can amplify the lepton asymmetry in the early universe during the phase transition. We present the baryon asymmetry interpretation requirement on certain parameter spaces of the phase transition and the primordial magnetic field.