Bubble Baryogenesis

TL;DR

This paper introduces a novel baryogenesis mechanism involving asymmetric bubble nucleation during a first-order phase transition, generating baryon asymmetry with potential observable signatures like gravitational waves.

Contribution

It presents a new bubble baryogenesis model with explicit B and CP violation, including numerical analysis and potential realizations in supersymmetric frameworks.

Findings

Numerical simulation of baryon asymmetry evolution during bubble dynamics

Identification of gravitational wave signatures from bubble collisions

Potential link to asymmetric dark matter generation

Abstract

We propose an alternative mechanism of baryogenesis in which a scalar baryon undergoes a percolating first-order phase transition in the early Universe. The potential barrier that divides the phases contains explicit B and CP violation and the corresponding instanton that mediates decay is therefore asymmetric. The nucleation and growth of these asymmetric bubbles dynamically generates baryons, which thermalize after percolation; bubble collision dynamics can also add to the asymmetry yield. We present an explicit toy model that undergoes bubble baryogenesis, and numerically study the evolution of the baryon asymmetry through bubble nucleation and growth, bubble collisions, and washout. We discuss more realistic constructions, in which the scalar baryon and its potential arise amongst the color-breaking minima of the MSSM, or in the supersymmetric neutrino seesaw mechanism. Phenomenological consequences, such as gravitational waves, and possible applications to asymmetric dark-matter generation are also discussed.