Related papers: Tree-level metastability bounds for the most gener…
We consider a Two-Higgs-Doublet Model (2HDM) constrained by the condition that assures cancellation of quadratic divergences up to the leading two-loop order. Regions in the parameter space consistent with existing experimental constraints…
If the Higgs mass m_H is as low as suggested by present experimental information, the Standard Model ground state might not be absolutely stable. We present a detailed analysis of the lower bounds on m_H imposed by the requirement that the…
We study the vacuum behavior of an extended Higgs sector with two doublets in a scenario with a softly broken \texorpdfstring{$U(1)$}{lg} global symmetry. The soft-violation term is introduced to avoid massless-axion particles arising when…
We perform a systematic study of generic accidental Higgs-family and CP symmetries that could occur in the two-Higgs-doublet-model potential, based on a Majorana scalar-field formalism which realizes a subgroup of GL(8,C). We derive the…
Scalar triplet extensions of the Standard Model provide an interesting playground for the explanation of neutrino mass suppression through the type-II seesaw mechanism. Propelled by the possible connections with leptonic CP violation, we…
The Higgs sector of the Next-to-Minimal Two-Higgs-Doublet Model (N2HDM) is obtained from the Two-Higgs-Doublet Model (2HDM) containing two complex Higgs doublets, by adding a real singlet field. In this paper, we analyse the vacuum…
We perform an exhaustive analysis of the most general Higgs sector of the minimal left-right symmetric model (MLRM). We find that the CP properties of the vacuum state are connected to the Higgs spectrum: if CP is broken spontaneously, the…
We study the vacuum behavior at one loop level in extended Higgs sectors with two doublets (2HDM), where $U(1)$ and $Z_{2}$ symmetries are considered to protect the $CP$ symmetry in the Higgs potential and to avoid Flavor Changing Neutral…
We study the most popular scalar extension of the Standard Model, namely the Two Higgs doublet model, extended by a complex triplet scalar (2HDMcT). Such considering model with a very small vacuum expectation value, provides a solution to…
I rebuild a conventional two-Higgs doublet model by relaxing the spontaneous CP violation and considering approximate global U(1) family symmetries. So that the domain-wall problem does not explicitly arise at the weak scale, but CP…
Two-Higgs-Doublet Models (2HDMs) are amongst the simplest extensions of the Standard Model. Such models allow for tree-level CP Violation (CPV) in the Higgs sector. We analyse a class of CPV 2HDM (of Type-I) in which only one of the two…
Assuming that the axion mechanism of solving the strong CP problem does not exist and the vanishing of theta at tree level is achieved by some model-building means, we study the naturalness of having large CP-violating sources in the…
We derive a sum rule which shows how to extend LEP limits on the masses of the lightest CP-even and CP-odd Higgs bosons of a CP-conserving two-Higgs-doublet model to any two Higgs bosons of a general CP-violating two-Higgs-doublet model. We…
We discuss the $Z_2$ symmetric two Higgs doublet model with a real soft breaking term (real 2HDM). We explain in detail why it is not tenable to assume CP conservation in the scalar sector to keep the dimension two term real, while CP is…
The complex singlet-doublet model is a popular theory to account for dark matter and electroweak baryogenesis, wherein the Standard Model particle content is supplemented by a complex scalar gauge singlet, with certain discrete symmetries…
The so-called metastability bound on the Higgs mass suggests that the smallness of the Higgs mass may be a byproduct of the metastability of the electroweak vacuum. A significantly strong bound requires new physics capable of lowering the…
We analyze a model for the Higgs sector with two scalar doublets and a $Z_2$ symmetry that is manifest in the Yukawa sector but broken in the potential. Thus, one of the doublets breaks the electroweak symmetry and has tree-level Yukawa…
We find a large CP violation effect within the Two-Higgs-Doublet-Model for the reaction $e^+e^-\to t\bar{t}H^0$ at future linear colliders. The CP-asymmetry arises already at the tree level as a result of interference between diagrams with…
LHC has found hints for a Higgs particle of 125 GeV. We investigate the possibility that such a particle is a mixture of scalar and pseudoscalar states. For definiteness, we concentrate on a two Higgs doublet model with explicit CP…
The two-Higgs-doublet model can be constrained by imposing Higgs-family symmetries and/or generalized CP symmetries. It is known that there are only six independent classes of such symmetry-constrained models. We study the CP properties of…