Baryogenesis at the electroweak phase transition

TL;DR

This paper explores how the electroweak phase transition could explain the universe's baryon asymmetry, analyzing the phase transition dynamics within the standard model at finite temperature.

Contribution

It investigates the electroweak phase transition's nature and strength using one-loop effective potential calculations, highlighting the dependence on Higgs and top quark masses.

Findings

The phase transition is of first order at one loop.

Finite temperature effects are well approximated by high temperature expansion.

Transition strength varies with Higgs and top quark masses.

Abstract

A possible solution to the observed baryon asymmetry in the universe is described, based on the physics of the standard model of electroweak interactions. At temperatures high enough electroweak physics provides violation of baryon number, while C and CP symmetries are not exactly conserved, although in the context of the minimal electroweak model with one Higgs doublet the rate of CP violation is not sufficient enough to generate the observed asymmetry. The condition that the universe must be out of thermal equilibrium requires the electroweak phase transition (EWPT) to be first order. The dynamics of the phase transition in the minimal model is investigated through the effective potential, which is calculated at the one loop order. Finite temperature effects on the effective potential are treated numerically and within the high temperature approximation, which is found to be in good agreement with the exact calculation. At the one loop level the phase transition was found to be of the first order, while the strength of the transition depends on the unknown parameters of the theory which are the Higgs boson and top quark masses.