Electroweak Baryogenesis and Colored Scalars

TL;DR

This paper investigates how 2-loop effects involving colored scalars at finite temperature can significantly strengthen the electroweak phase transition, impacting baryogenesis and suggesting new experimental searches.

Contribution

It demonstrates that colored scalars contribute stronger 2-loop effects to the effective potential, enhancing the electroweak phase transition and influencing baryogenesis models.

Findings

2-loop effects with colored scalars can triple the phase transition strength

Colored scalars favor electroweak baryogenesis over singlet scalars

Results motivate searches for di-jet resonances and jets with missing energy

Abstract

We consider the 2-loop finite temperature effective potential for a Standard Model-like Higgs boson, allowing Higgs boson couplings to additional scalars. If the scalars transform under color, they contribute 2-loop diagrams to the effective potential that include gluons. These 2-loop effects are perhaps stronger than previously appreciated. For a Higgs boson mass of 115 GeV, they can increase the strength of the phase transition by as much as a factor of 3.5. It is the analogue of this effect that is responsible for the survival of the tenuous electroweak baryogenesis window of the Minimal Supersymmetric Standard Model. We further illuminate the importance of these 2-loop diagrams by contrasting models with colored scalars to models with singlet scalars. We conclude that baryogenesis favors models with light colored scalars. This motivates searches for pair-produced di-jet resonances or jet(s) + missing energy.