Electroweak baryogenesis in a scale invariant model and Higgs phenomenology

TL;DR

This paper investigates electroweak baryogenesis within a scale-invariant two Higgs doublet model, analyzing phase transition dynamics, sphaleron energy, and Higgs phenomenology, consistent with LHC data and potential deviations from Standard Model predictions.

Contribution

It provides the first evaluation of sphaleron energy in this model and links the electroweak phase transition to observable Higgs decay and coupling deviations.

Findings

Strong first-order phase transition is necessary for baryogenesis.

Higgs decay to two gammas could be reduced by 10%.

Triple Higgs coupling could increase by 82%.

Abstract

We study the electroweak phase transition and the critical bubble in the scale-invariant two Higgs doublet model taking the recent LHC data into account. The sphaleron energy in this model is evaluated for the first time. It is found that the strong first-order electroweak phase transition is the inevitable consequence to be consistent with the observed 125 GeV Higgs boson. In such a case, the signal strength of the Higgs decay to two gammas and the triple Higgs boson coupling could deviate from the SM values by $-10$% and $+82$%, respectively.