Tree-level metastability bounds for the most general two Higgs doublet model

TL;DR

This paper establishes tree-level bounds on the scalar potential of the most general two Higgs doublet model to ensure the current vacuum is stable, introducing a new, more general and practical method applicable to CP-violating sectors.

Contribution

It presents a novel, comprehensive procedure for deriving metastability bounds in the general 2HDM, applicable to both CP-conserving and CP-violating cases, improving upon previous methods.

Findings

Derived new stability conditions for the general 2HDM scalar potential.

Applied the bounds to the Z2 model with CP violation.

Provided a more practical approach for vacuum stability analysis.

Abstract

Within two Higgs doublet models, it is possible that the current vacuum is not the global minimum, in which case it could possibly decay at a later stage. We discuss the tree-level conditions which must be obeyed by the most general scalar potential in order to preclude that possibility. We propose a new procedure which is not only more general but also easier to implement than the previously published one, including CP conserving as well as CP violating scalar sectors. We illustrate these conditions within the context of the Z2 model, softly broken by a complex, CP violating parameter.