Tree-level unitarity constraints in the most general two Higgs doublet model

Abstract

We obtain tree-level unitarity constraints for the most general Two Higgs Doublet Model (2HDM) with explicit CP -violation. We briefly discuss correspondence between possible violation of tree level unitarity limitation and physical content of the theory.The Electroweak Symmetry Breaking in the Standard Model is described usually with the Higgs mechanism. In its simplest variant, an initial Higgs field is an isodoublet of scalar fields with weak isospin σ. The simplest extension of the Higgs sector known as two-Higgs-doublet model (2HDM) consists in introducing two Higgs weak isodoublets of scalar fields φ 1 and φ 2 with hypercharge Y = +1 (for a review, see [1] and [2]).We consider the Higgs potential of 2HDM in the form

h → Zγ in the complex two Higgs doublet model

“…below solution [31], conforming to perturbative unitarity [32][33][34], and the oblique radiative parameters S, T, U [35,36]. After implementing this algorithm, we have a collection of possible C2HDM data points.…”

Strong first order electroweak phase transition in the CP-conserving 2HDM revisited

“…In order to obtain viable data sets we use ScannerS [80,81] to perform extensive scans in the 2HDM parameter space and check for compatibility with the constraints. The program verifies if the tree-level potential is bounded from below by applying the conditions given in [82] and checks for tree-level perturbative unitarity as described in [83]. In the CP-conserving 2HDM investigated here, the requirement that the neutral CP-even tree-level minimum is the global one is tested through a simple condition [84].…”

Large pseudoscalar Yukawa couplings in the complex 2HDM

“…All points comply to the following theoretical constraints: the potential is bounded from below [49], perturbative unitarity is enforced [50][51][52] and all allowed points conform to the oblique radiative parameters [53][54][55].…”