Phase Transition in the Aligned Two-Higgs Doublets Model When the Goldstone Theorem is Conserved

This paper studies the phase transition in the aligned two-Higgs doublet model by applying the Cornwall-Jackiw-Tomboulis effective potential in the double-bubble approximation. Its main feature is that the Goldstone theorem is restored in the model by adjusting the CJT effective potential, and the phase transition is of the second-order type, following the symmetry restoration scenario.