We consider a left-right symmetric extension of the Standard Model where the spontaneous breakdown of the left-right symmetry is triggered by doublets. The electroweak $ρ$ parameter is protected from large corrections in this Doublet Left-Right Model (DLRM), contrary to the triplet case. This allows in principle for more diverse patterns of symmetry breaking. We consider several constraints on the gauge and scalar sectors of DLRM: the unitarity of scattering processes involving gauge bosons with longitudinal polarisations, the radiative corrections to the muon $Δr$ parameter and the electroweak precision observables measured at the $Z$ pole and at low energies. Combining these constraints within the frequentist CKMfitter approach, we see that the fit pushes the scale of left-right symmetry breaking up to a few TeV, while favouring an electroweak symmetry breaking triggered not only by the $ SU(2)_L \times SU(2)_R $ bi-doublet, which is the case most commonly considered in the literature, but also by the $ SU(2)_L $ doublet.
We give a survey on current constraints on the Inert Doublet Model parameter space, including all theoretical as well as experimental limits from collider and astrophysical data. For allowed regions in the parameter space, we provide total production cross sections for the pair-production of scalars at the 13 TeV LHC and propose benchmarks scenarios which should be investigated by the LHC experiments at Run II.
The recent discovery of a Standard Model-like boson with mass of about 126 GeV seems to be the first direct information on the electroweak symmetry breaking mechanism. Using the available experimental data from the LHC and Tevatron we study the implications on the parameter space of the Two-Higgs Doublet Model extension of the Standard Model. The generic structure of the Aligned Two-Higgs Doublet model is imposed in the Yukawa sector; also the models with discrete $\mathcal{Z}_2$ symmetries are analyzed.
We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter condition can be used to limit the amount of Z2 symmetry breaking allowed in a given model.
In this work, we use a recast of the Run II search for invisible Higgs decays within Vector Boson Fusion to constrain the parameter space of the Inert Doublet model, a two Higgs doublet model with a dark matter candidate. When including all known theoretical as well as collider constraints, we find that the above can rule out a relatively large part in the mH-lambda345 parameter space, for dark scalar masses mH <= 100 GeV. Including the latest dark matter constraints, a smaller part of parameter space remains which is solely excluded from the above analysis. We also discuss the sensitivity of …
Left-Right Models (LRM) attempt at giving an understanding of the violation of parity (or charge-conjugation) by the weak interactions in the SM through a similar description of left- and right-handed currents at high energies. The spontaneous symmetry breaking of the LRM gauge group is triggered by an enlarged Higgs sector, usually consisting of two triplet fields (left-right symmetry breaking) and a bidoublet (electroweak symmetry breaking). I reconsider an alternative LRM with doublet instead of triplet fields. After explaining some features of this model, I discuss constraints on its param…
We confront the Two-Higgs-Doublet Model with a variety of experimental constraints as well as theoretical consistency conditions. The most constraining data are the \bar B\to X_sγdecay rate (at low values of M_{H^\pm}), and Δρ(at both low and high M_{H^\pm}). We also take into account the B\bar B oscillation rate and R_b, or the width Γ(Z\to b\bar b) (both of which restrict the model at low values of \tanβ), and the B^-\toτν_τdecay rate, which restricts the model at high \tanβand low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs boson is considered, as well as the mu…
The Dark 2HDM (called also the Inert Doublet Model) is the version of the Two-Higgs-Doublet Model with an exact $Z_2$ symmetry. It contains the SM-like Higgs boson $h$ and dark scalars $H$,$H^+,H^-$,$A$. Only dark scalars have odd $Z_2$ parity and therefore the lightest of them can be a dark matter candidate. The comparison of such model and of the standard 2HDM with an explicit $Z_2$ symmetry is given.
We study the theoretical and phenomenological constraints imposed on the scalar sector of the gauged two Higgs doublet model proposed recently as a variant of the popular inert Higgs doublet model of dark matter. The requirements of tree-level vacuum stability and perturbative unitarity in the scalar sector are analyzed in detail. Furthermore, taking into account the constraints from the 125 GeV Higgs boson measurements at the Large Hadron Collider, we map out the allowed ranges for the fundamental parameters of the scalar potential in the model.
A general method for classifying the possible quark models of a multi-Higgs-doublet model, in the presence of Abelian symmetries, is presented. All the possible sets of textures that can be present in a given sector are shown, thus turning the determination of the flavor models into a combinatorial problem. Several symmetry implementations are studied for two and three Higgs doublet models. Some models implementations are explored in great detail, with a particular emphasis on models known as Branco-Grimus-Lavoura and nearest-neighbour-nnteraction. Several considerations on the flavor changing…
Interesting contributions to $Δa_μ$ from a two-Higgs-doublet-model is coming from a two-loop Barr-Zee diagram for most part of the parameter space -- a fact that has been overlooked by some Higgs/SUSY experts. A definite positive contribution has requirements that go against precision EW data and other known constraints. For the case without SUSY, in particular, this is almost enough to kill the two-Higgs-doublet-model (II). We will discuss the interplay of all the constraints and their implications.
Classifying the symmetries of the scalar sector in multi-Higgs-doublet models is the main focus of this thesis. We have found certain symmetries that are always broken in models with more than two doublets, which we name "frustrated symmetries". In the attempt towards the classification of possible symmetries in the scalar sector of the NHDM, we find that these symmetry groups are either subgroups of the maximal torus, or certain finite Abelian groups which are not subgroups of maximal tori. For the subgroups of the maximal torus, we present an algorithmic strategy that gives the full list of …
We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos--Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The μterm of order TeV is found to be naturally induced. A Z_2-assisted anomalous U(1)_A gauge symmetry plays a crucial role in achieving these results. The thresh…
In supersymmetric standard models with multi Higgs doublet fields, selfcoupling constants in the Higgs potential come only from the D-terms at the tree level. We investigate the decoupling property of additional two heavier Higgs doublet fields in the supersymmetric standard model with four Higgs doublets. In particular, we study how they can modify the predictions on the quantities well predicted in the minimal supersymmetric standard model (MSSM), when the extra doublet fields are rather heavy to be measured at collider experiments. The B-term mixing between these extra heavy Higgs bosons an…
Lee-Wick partners to the Standard Model Higgs doublet may appear at a mass scale that is significantly lower than that of the remaining Lee-Wick partner states. The relevant effective theory is a two-Higgs doublet model in which one doublet has wrong-sign kinetic and mass terms. We determine bounds on this effective theory, including those from neutral B-meson mixing, b --> X_s gamma, and Z --> b b-bar. The results differ from those of conventional two-Higgs doublet models and lead to meaningful constraints on the Lee-Wick Higgs sector.
I present comprehensive analyses of the viable parameter regions of the Standard Model of particle physics and two of its extensions: the Standard Model with four fermion generations and the Two-Higgs-Doublets model of type II. Applying frequentist methods, I have performed global fits which show that the Standard Model is compatible with electroweak precision data and the measured Higgs signal strengths. The Standard Model with four generations is excluded by the experimental results with a p-value corresponding to more than five standard deviations. In the Two-Higgs-Doublets model of type II…
We analyze the scalar sector properties of a general class of two-Higgs-doublet models which has a global U(1) symmetry in the quartic terms. We find constraints on the parameters of the potential from the considerations of unitarity of scattering amplitudes, the global stability of the potential and the $ρ$-parameter. We concentrate on the spectrum of the non-standard scalar masses in the decoupling limit which is preferred by the Higgs data at the LHC. We exhibit charged-Higgs induced contributions to the diphoton decay width of the 125\,GeV Higgs boson and its correlation with the correspon…
We present an extensive analysis of a model in which the (Majorana) Dark Matter candidate is a mixture between a SU(2) singlet and two SU(2) doublets. This kind of setup takes the name of singlet-doublet model. We will investigate in detail an extension of this model in which the Dark Matter sector interactions with a 2-doublet Higgs sector enforcing the complementarity between Dark Matter phenomenology and searches of extra Higgs bosons.
We embed Two Higgs Doublet Models (2HDMs) in the Froggatt Nielsen (FN) framework. We find that the approximate FN symmetry predicts i) approximate Natural Flavor Conservation (NFC) of Types II or IV in the Yukawa sector, and ii) approximate Peccei-Quinn (PQ) symmetry in the scalar sector. We discuss the phenomenological consequences of these features.
In this proceeding, I summarize results on various new physics extensions of the Standard Model, for models with and without dark matter candidates. I discuss current constraints as well as rates and discovery prospects at future colliders.
Recent experimental results on exclusive semi-tauonic B meson decays show sizable deviations from the standard model prediction, while the recent result on pure-tauonic decay reduces the deviation from the prediction. These results suggest an indirect evidence of new physics in which the structure of the relevant weak charged interaction may differ from that of the standard model. We study these tauonic B decays in the context of extensions of the Higgs sector. As a result, we find that two Higgs doublet models without tree-level FCNC are unlikely to explain the present experimental data while…
We investigate the constraints on the leptoquark Yukawa couplings and Higgs-leptoquark quartic couplings for scalar doublet leptoquark $\tilde{R}_2$, scalar triplet leptoquark $\vec S_3$ and their combination with both three generations and one generation from perturbative unitarity and vacuum stability. Perturbative unitarity of all the dimensionless couplings have been studied via one- and two-loop beta-functions. Introduction of new $SU(2)$ multiplets in terms of these leptoquarks fabricate Landau poles at two-loop level in the gauge coupling $g_2$ at $10^{19.7}$ GeV and $10^{14.4}$ GeV, re…
We study parameters of an extended standard model. The neutrino sector is enlarged by one or two right-handed singlet fields and the Higgs sector contains one additional doublet. One-loop radiative corrections generate the mass for the light neutrino fields. The numerical analysis is performed varying the masses of heavy neutrinos and of the additional neutral Higgses. The parameters of the neutrino sector, allowing for the seesaw type-I mechanism, are restricted by experimental neutrino oscillation data. Both normal and inverted hierarchies of the light neutrino masses are discussed.
We consider the doublet-triplet fermionic model in the scheme of the custodial limit when the dark matter (DM) candidate is pure doublet and lies at the electroweak scale. This scheme, despite being an appealing and promising DM model, is severely constrained by the interplay between the DM relic density constraint and the LHC measurement of the Higgs diphoton decay rate. In this work, the DM relic density is considered to arise from either a nonstandard cosmology scenario or as a part of a larger sector encompassing other DM particles, this in order to saturate the observed relic abundance. F…
In the two Higgs doublet model with no additional symmetries in the scalar sector (different from the gauge and Lorentz symmetries), it is customary to reparameterize the model by rotating the scalar doublets such that one of the vacuum expectation values vanishes. It is well known that the Yukawa sector of the model is unaffected by such transformation. Notwithstanding, since the Higgs potential must also be transformed, it is necessary to show that such sector is also unaltered in its physical content. We demostrate that the physical content of the potential is invariant even when the charge…
We study the constraints on the new parameters in the gauge sector of gauged two Higgs doublet model using the electroweak precision test data collected from the Large Electron Positron Collider (LEP) at and off the Z-pole as well as the current Drell-Yan and high-mass dilepton resonance data from the Large Hadron Collider (LHC). Impacts on the new parameters by the projected sensitivities of various electroweak observables at the Circular Electron Positron Collider (CEPC) proposed to be built in China are also discussed. We also clarify why the Stüeckelberg mass $M_Y$ for the hypercharge $U(1…
Recently, the CDF collaboration has reported a new precision measurement of the $W$-boson mass, $M_W$, showing a large deviation from the value predicted by the Standard Model (SM). In this paper, we analyse possible new physics contributions to $M_W$ from extended Higgs sectors. We focus on the Two-Higgs-Doublet Model (2HDM) as a concrete example. Employing predictions for the electroweak precision observables in the 2HDM at the two-loop level and taking into account further theoretical and experimental constraints, we identify parameter regions of the 2HDM in which the prediction for $M_W$ i…
In the two Higgs doublet model, natural flavour conservation can be achieved through the use of a discrete Z2 symmetry. A less restrictive condition is the requirement of alignment in the Yukawa sector. So far, alignment has been an anzatz, not rooted in a specific model. In this letter we present a model for alignment, which starts with 2+N Higgs doublets, with natural flavour conservation imposed by a discrete symmetry. Only two of these scalars couple to the fermions, the other N scalars are in a hidden sector. Assuming that the two scalar doublets coupled to fermions are heavy, their decou…
Maximally Symmetric $n$-Higgs Doublet Models (MS-$n$HDMs)define very economic settings that enable sharp Higgs-sector predictions beyond the Standard Model (SM) potentially testable at high-energy colliders. The scalar potential of a MS-$n$HDM obeys an $\mathrm{Sp(2}n)$ symmetry, which is softly broken by bilinear scalar masses and explicitly by hypercharge and Yukawa couplings through renormalisation-group effects. The $\mathrm{Sp(2}n)$ also ensures natural SM alignment and allows for quartic coupling unification up to the Planck scale. As typical examples, we consider maximally symmetric rea…
We study the simplest Two-Higgs-Doublet Model that allows for CP nonconservation, where it can be parametrized by only one parameter in the Higgs potential. Different concepts of maximal CP-nonconservation in the gauge-Higgs and the quark-Higgs (Yukawa) sectors are compared. Maximal CP nonconservation in the gauge-Higgs sector does normally not lead to maximal CP nonconservation in the Yukawa sector, and vice versa.
We review recent work on constraining the parameter space of the Two-Higgs-Doublet Model by theoretical and experimental results. Some characteristics of the model, in particular the distribution of masses in the surviving parameter space, are discussed.
We introduce the public computer code HiggsSignals, which can be used to test the predictions from models with arbitrary Higgs sectors against experimental measurements. Following a brief description of the code, several examples of HiggsSignals applications are given. We derive constraints on extended Higgs sectors taking into account the measured rates for the observed LHC Higgs signal in all available channels. The results are presented both in a model-independent framework with coupling scale factors that parametrize deviations from the Standard Model, and in a model-dependent example wher…
We propose a natural Higgs sector in E_6 grand unified theory (GUT) with anomalous U(1)_A gauge symmetry. In the scenario, the doublet-triplet splitting can be realized while the proton decay via dimension 5 operator is suppressed. The gauge coupling unification is also realized without finetuning. The GUT scale is generally lower than the usual GUT scale 2\times 10^{16} GeV, the proton decay via dimension 6 operator can be seen in near future experiment. The lifetime of nucleon in the model is roughly estimated as τ_p(p\to e^+π^0)\sim 3\times 10^{33} years. It is shown that the Higgs sector i…
A vast literature on the theory and phenomenology of Two-Higgs-Doublet models (2HDM) exists since long. However, the present situation demands a revisit of some 2HDM properties. Now that a 125 GeV scalar resonance has been discovered at the LHC, with its couplings to other particles showing increasing affinity to the Standard Model Higgs-like behavior, the 2HDM parameter space is more squeezed than ever. We briefly review the different parametrizations of the 2HDM potential and discuss the constraints on the parameter space arising from the unitarity and stability of the potential together wit…
The minimal supersymmetric standard model involves a rather restrictive Higgs potential with two Higgs fields. Recently, the full set of classes of symmetries allowed in the most general two Higgs doublet model was identified; these classes do not include the supersymmetric limit as a particular class. Thus, a physically meaningful definition of the supersymmetric limit must involve the interaction of the Higgs sector with other sectors of the theory. Here we show how one can construct basis invariant probes of supersymmetry involving both the Higgs sector and the gaugino-higgsino Higgs intera…
In this proceeding, I discuss several models that extend the scalar sector of the Standard Model by additional matter states. I here focus on results for models with singlet extensions, which have been obtained recently and update some of the results presented in previous work. In more detail, I will briefly review the option to test a strong first-order electroweak phase transition using precision measurements in the electroweak sector, as well as production cross-sections for non-standard scalar production at Higgs factories.
We study the mass, the mixing and the coupling with $Z$ boson of the lightest Higgs boson in the next-to-minimal supersymmetric standard model. The vacuum structure of the Higgs potential is analyzed and the new false vacua are discussed. The significant parameter region can be excluded by requiring that the realistic vacuum is deeper than false vacua, which result in constraints on the properties of the lightest Higgs boson.
The new phenomenon of symbiotic symmetries is described in the context of the Two-Higgs-Doublet Model (THDM). The quartic potential has two or more separate sectors with unequal symmetries, but these unequal symmetries persist even though the different sectors are renormalized by one another. We discuss all such symmetries of the THDM, consistent with the SU(2) x U(1) gauge interactions, using the Pauli formalism.
In this paper, we construct an effective model that describes the electroweak symmetry breaking sector by means of composite Higgs-like scalars, following the ideas of Minimal Walking Technicolor (MWT). We argue that, because of the general failure of Extended Technicolor (ETC) to explain the mass of the top quark, it is necessary to introduce two composite Higgs bosons: one of them originated by a MWT-ETC sector and the other one produced by a Topcolor sector. We focus on the phenomenological differences between the light composite Higgs present in our model and the fundamental Higgs boson pr…
We study all implementations of the $S_3$ symmetry in the two Higgs doublet model with quarks, consistent with non-zero quark masses and a Cabibbo-Kobayashi-Maskawa (CKM) matrix which is not block diagonal. We study the impact of the various soft-breaking terms and vacuum expectation values, and find an interesting relation between $α$ and $β$. We also show that, in this minimal setting, only two types of assignments are possible: either all field sectors are in singlets or all field sectors have a doublet.
We construct an equation of state (EOS) for neutron stars by interpolating hadronic EOS at low density and quark EOS at high density. A hadronic model based on the parity doublet structure is used for hadronic matter and a quark model of Nambu--Jona-Lasinio type is for quark matter. We assume crossover between hadronic matter and quark matter in the the color-flavor locked phase. The nucleon mass of the parity doublet model has a mass associated with the chiral symmetry breaking, and a chiral invariant mass $m_0$ which is insensitive to the chiral condensate. The value of $m_0$ affects the nuc…
We study CP-Violation (CPV) in a Composite 2-Higgs Doublet Model (C2HDM) based on the global symmetry breaking $SO(6)/[SO(4)\times SO(2)]$, wherein the strong sector is modeled by a two-site moose structure. Non-trivial complex phases in the interactions involving fermions in both the elementary and strong sectors can induce CPV in the Higgs potential as well as the Yukawa coupling parameters. We compute both of the latter and analyse their dependence upon the aforementioned complex phases. Finally, we discuss physics observables which are distinctive of this model. Even in the simplest case w…
We present the implementation of heavy stable charge particle (HSCP) and R-hadron signatures into SModelS v1.2. We include simplified-model results from the 8 and 13 TeV LHC and demonstrate their impact on two new physics scenarios motivated by dark matter: the inert doublet model and a gravitino dark matter scenario. For the former, we find sensitivity up to dark matter masses of 580 GeV for small mass splittings within the inert doublet, while missing energy searches are not able to constrain any significant part of the cosmologically preferred parameter space. For the gravitino dark matter …
The natural cutoff scale for the quadratically divergent top quark contribution to the Higgs mass parameter can be significantly raised above the surprisingly low standard model value, with important consequences for the LHC: the physics that cancels the top quark divergence may be out of reach, while an electroweak sector with "improved naturalness" may be discovered. Such a sector, consistent with electroweak precision tests, arises in the two Higgs doublet model with heavy Higgs and top quark interactions that approach strong coupling.
We investigate the role of a local $U(1)'$ symmetry for the problem of CP violation in the effective theory for two Higgs doublet models and its microscopic counterparts. First, in two Higgs doublet models with $U(1)'$, we show that the higher-dimensional operators in the scalar potential violate the CP symmetry with an interplay with the mixing mass parameter, giving rise to small mixings between CP-even and CP-odd scalars. Motivated by the $B$-meson anomalies in recent years, we take the flavored $U(1)'$ to be a benchmark model for specifying the flavor structure. Then, we calculate the elec…
We study extensions of the Standard Model (SM) in which copies of the SM scalar SU(2) doublet are added to the Higgs sector. These scalar doublets either acquire a Vacuum Expectation Value (VEV) and hence are active or do not develop a VEV and are inert. We consider CP-violation (CPV) in both the active and inert sector. As an example of a model with CPV in the active sector, we present a Type-I 2-Higgs-Doublet Model (2HDM) with two active doublets and show Large Hadron Collider (LHC) signals of such a scenario. The amount of CPV in this case is very limited due to constraints coming from Elec…
We explore the implications of a 126 GeV Higgs boson indicated by the recent LHC results for two-Higgs doublet model (2HDM). Identifying the 126 GeV Higgs boson as either the lighter or heavier of CP even neutral Higgs bosons in 2HDM, we examine how the masses of Higgs fields and mixing parameters can be constrained by the theoretical conditions and experimental constraints. The theoretical conditions taken into account are the vacuum stability, perturbativity and unitarity required to be satisfied up to a cut-off scale. We also show how bounds on the masses of Higgs bosons and mixing paramete…
Models with extended quark sector affect the CP asymmetry in the $B\to ψK_{S}$ decay, $a_{ψK_{S}}$, in two ways: First, the top-mediated box diagram is not necessarily the only important contribution to $B-\bar{B}$ mixing. Second, the $3\times 3$ CKM matrix is no longer unitary. We analyze the constraints that follow from the CDF measurement, $a_{ψK_{S}} =0.79^{+0.41}_{-0.44}$, on the mixing parameters of extended quark sectors. Most noticeably, we find significant constraints on the phase of the relevant flavor changing $Z$ coupling in models with extra down quarks in vector-like representati…
The Two-Higgs-Doublet Model is considered, in its CP-non-conserving version. It is shown quantitatively how vacuum stability and tree-level unitarity in the Higgs-Higgs-scattering sector constrain the parameter space of the model. In particular, at high values of tanbeta, the model violates unitarity, unless some of the Higgs bosons are heavy. In the regime of large CP violation in the neutral-Higgs-t-quark sector, which requires tanbeta lsim 1, the Yukawa coupling parameter space (determined by the neutral-Higgs-sector rotation matrix) is reasonably unconstrained. On the other hand, the corre…
Different approaches are used for the calculation of the SM-like Higgs boson mass in the MSSM: the fixed-order diagrammatic approach is accurate for low SUSY scales; the EFT approach,for high SUSY scales. Hybrid approaches, combining fixed-order and EFT calculations, allow to obtain a precise prediction also for intermediary SUSY scales. Here, we briefly discuss the hybrid approach implemented into the code FeynHiggs. In addition, we show how the refined Higgs mass prediction was used to define new MSSM Higgs benchmark scenarios.
Extended Higgs sectors appear in many models for physics beyond the Standard Model. Current Higgs measurements at the LHC are starting to significantly constrain them. We study their Higgs coupling patterns at tree level as well as including quantum corrections. Our benchmarks include a dark singlet-doublet extension and several two-doublet setups. Using SFitter we translate the current Higgs coupling measurements for one light Higgs state into their respective parameter spaces. Finally, we show how two-Higgs-doublet models can serve as a consistent ultraviolet completion of an assumed single …
It has been known since decades that imposing a symmetry group G on the scalar sector of multi-Higgs-doublet models has consequences for CP-violation. In all examples of two- and three-Higgs-doublet models equipped with symmetries, one observes the following intriguing property: if G prevents explicit CP-violation (CPV), at least in the neutral Higgs sector, then it also prevents spontaneous CPV, and if G allows explicit CPV, then it allows for spontaneous CPV. One is led to conjecture that this is a general phenomenon. In this paper, we prove this conjecture for any rephasing symmetry group G…
Upper bounds at the weak scale are obtained for all $λ_{ij}λ_{im}$ type product couplings of the scalar leptoquark model which may affect K-K(bar), B_d-B_d(bar), and B_s-B_s(bar)$ mixing, as well as leptonic and semileptonic K and B decays. Constraints are obtained for both real and imaginary parts of the couplings. We also discuss the role of leptoquarks in explaining the anomalously large CP-violating phase in B_s-B_s(bar) mixing.
We analyze the compatibility between abelian symmetries acting in two different sectors of a theory using the Smith Normal Form method. We focus on N-Higgs-doublet models (NHDMs) and on the compatibility between symmetries in the Higgs potential and in the Yukawa interactions, which were separately analyzed previous works. It is shown that two equal (isomorphic) symmetry groups that act in two separate sectors are not necessarily compatible in the whole theory and an upper bound is found for the size of the group that can be implemented in the entire NHDM. We also develop useful techniques to …
The inert doublet model is an extension of the Standard Model of Elementary Particles that is defined by the only addition of a second Higgs doublet without couplings to quarks or leptons. This minimal framework has been studied for many reasons. In particular, it has been suggested that the new degrees of freedom contained in this doublet can account for the Dark Matter of the Universe.
