Two Higgs bidoublet model with spontaneousPandCPviolation and decoupling limit to the two Higgs doublet model

Abstract

The two Higgs bidoublet left-right symmetric model (2HBDM) as a simple extension of the minimal left-right symmetric model with a single Higgs bidoublet is motivated to realize both spontaneous parity ($P$) violation and charge conjugation and parity ($CP$) violation while consistent with the low-energy phenomenology without significant fine-tuning. By carefully investigating the Higgs potential of the model, we find that sizable $CP$-violating phases are allowed after the spontaneous symmetry breaking. The mass spectra of the extra scalars in the 2HBDM are significantly different from the ones in the minimal left-right symmetric model. In particular, we demonstrate in the decoupling limit when the right-handed gauge-symmetry-breaking scale is much higher than the electroweak scale, the 2HBDM decouples into the general two Higgs doublet model with spontaneous $CP$ violation and has rich induced sources of $CP$ violation. We show that in the decoupling limit, it contains extra light Higgs bosons with masses around electroweak scale, which can be directly searched at the ongoing LHC and future International Linear Collider experiments.