New collider implications on a strongly first order EWPT

TL;DR

This paper discusses how collider experiments can test the nature of the electroweak phase transition, which is crucial for understanding baryogenesis, by analyzing deviations in Higgs couplings caused by new charged particles.

Contribution

It provides a model-independent method to determine conditions for a strongly first order electroweak phase transition using collider measurements of Higgs couplings.

Findings

Deviations in $hhh$ and $h ext{ extgamma} ext{ extgamma}$ couplings indicate the phase transition nature.

Future collider measurements can test the viability of electroweak baryogenesis.

Conditions for a strongly first order phase transition are derived independently of specific models.

Abstract

In order to understand the early history of the universe, and to test baryogenesis models, determining the nature of the electroweak phase transition is imperative. The order and strength of this transition is strongly correlated to relatively large deviations in the $hhh$ coupling. In models where a considerable part of the $hhh$ coupling deviation is caused by charged particle loops, the $h\gamma\gamma$ coupling is also expected to deviate considerably. In this talk, by using a model-independent approach, I explain how to obtain conditions that are sufficient for a strongly first order phase transition. After the $h\gamma\gamma$ coupling is determined with precision at the HL-LHC, these conditions can be tested at Future Linear Colliders by measurements of the $hhh$ coupling, to conclusively determine the nature of the electroweak phase transition and the viability of electroweak baryogenesis on models with new charged scalars.