- Accepted Paper
Fate of metastable vacua in the type-II two-Higgs-doublet model
Phys. Rev. D - Accepted 28 October, 2026
DOI: https://doi.org/10.1103/rd6l-1q9s
Phys. Rev. D - Accepted 28 October, 2026
DOI: https://doi.org/10.1103/rd6l-1q9s
The scalar potential of the Two-Higgs-Doublet Model (2HDM) can admit multiple non-degenerate vacua due to the presence of the two Higgs doublets unlike the Standard Model (SM). For a physically viable parameter point, one of these vacua must correspond to the physical electroweak (EW) symmetry breaking vacuum with the vacuum expectation value of about GeV. Given the complex structure of the scalar potential, the physical EW vacuum may be metastable in nature rather than the global minimum of the potential. In this work, we delineate regions of the parameter space in the Type-II 2HDM accommodating multiple extrema of the scalar potential and analyze, in a gauge-independent manner, the stability of the EW vacuum there at the tree level and beyond. A Bayesian global fit of the Type-II 2HDM, including next-to-leading-order (NLO) unitarity constraints and the latest experimental measurements, excludes the parameter space regions that lead to a metastable EW vacuum at both tree and one-loop level, after marginalizing over all other parameters. Additionally, we find that these regions are even more strongly excluded if the NLO perturbativity condition is imposed.
If the author has provided any supplemental materials with this article they will be available upon publication of the version of record.