Weakly First Order Cosmological Phase Transitions and Fermion Production

TL;DR

This paper investigates weakly first order cosmological phase transitions in electroweak theories, highlighting their unique dynamics and implications for electroweak baryogenesis, especially regarding sphaleron washout bounds.

Contribution

It introduces a new understanding of weakly first order transitions involving phase mixing and domain coarsening, differing from the traditional bubble nucleation picture.

Findings

Identifies Higgs mass regimes with significant phase mixing.

Describes domain coarsening dynamics in weakly first order transitions.

Explains how these dynamics can facilitate electroweak baryogenesis.

Abstract

We study weakly first order cosmological phase transitions in finite temperature field theories. Focusing on the standard electroweak theory and its minimal supersymmetric extension, we identify the regimes of Higgs masses for which the phase transition in these models proceeds by significant phase mixing and the coarsening of the subsequent domain network. This dynamics is distinct from that for strongly first order transitions, which proceed by the nucleation and propagation of critical bubbles. We describe how electroweak baryogenesis might take place in these models, explaining how our new picture can relax the sphaleron washout bound of traditional scenarios.