Gravitational Wave Signatures from Domain Wall and Strong First-Order Phase Transitions in a Two Complex Scalar extension of the Standard Model

Understand

We consider a simple extension of Standard Model by adding two complex singlet scalars with a $\rm{U}\left(1\right)$ symmetry.

• A discrete $\mathcal{Z}_2 \times \mathcal{Z}^{\prime}_2$ symmetry is imposed in the model and the added scalars acquire a non zero vacuum expectation value (VEV) when the imposed symmetry is broken spontaneously.
• The real (CP even) parts of the complex scalars mix with the SM Higgs and give three physical mass eigenstates.
• One of these physical mass eigenstates is attributed to the SM like Higgs boson with mass 125.09 GeV.