We propose a generic framework in which the Higgs and the unparticle are both composite. The underlying theories are four dimensional, asymptotically free, nonsupersymmetric gauge theories with fermionic matter. We sketch a possible uni- fication of these two sectors at a much higher scale resembling extended technicolor models. By construction our extensions are natural, meaning that there is no hierar- chy problem. The coupling of the unparticle sector to the composite Higgs emerges as a four-fermion operator. The bilinear unparticle operator near the electroweak scale has scaling dimension in the range 1 < dU < 3. We investigate, in various ways, the breaking of scale invariance induced by the electroweak scale resulting in an unparticle condensate. The latter acts as a natural infrared cut off or hadronic scale. We give the low-energy effective theory valid near the electroweak scale. The unparticle Higgs mixing is found to be suppressed within our framework.
We show that scalar unparticles coupled to the Standard Model Higgs at the renormalizable level can have a dramatic impact in the breaking of the electroweak symmetry already at tree level. In particular one can get the proper electroweak scale without the need of a Higgs mass term in the Lagrangian. By studying the mixed unparticle-Higgs propagator and spectral function we also show how unparticles can shift the Higgs mass away from its Standard Model value, λv^2, and influence other Higgs boson properties. Conversely, we study in some detail how electroweak symmetry breaking affects the unpa…
We study the effects of two-body Higgs boson scattering by exchanging unpsrticles. The unparticle contribution can change the standard model prediction for two-body Higgs boson scattering partial wave amplitude significantly leading to modification of the unitarity constraint on the standard model Higgs boson mass. For unparticle dimension $d_\U$ between 1 and 2, the unitarity constraint on Higgs boson mass can be larger than that in the SM. Information on unparticle interaction can also be obtained.
A renormalizable coupling between the Higgs and a scalar unparticle operator O_U of non-integer dimension d_U<2 triggers, after electroweak symmetry breaking, an infrared divergent vacuum expectation value for O_U. Such IR divergence should be tamed before any phenomenological implications of the Higgs-unparticle interplay can be drawn. In this paper we present a novel mechanism to cure that IR divergence through (scale-invariant) unparticle self-interactions, which has properties qualitatively different from the mechanism considered previously. Besides finding a mass gap in the unparticle con…
The decay of the standard model Higgs boson into a single photon and a vector unparticle through a one-loop process is studied. For an intermediate mass Higgs boson, this single photon plus unparticle mode can have a branching ratio comparable with the two-photon discovery mode. The emitted photon has a continuous energy spectrum encoding the nature of the recoil unparticle. It can be measured in precision studies of the Higgs boson after its discovery.
We study supersymmetric QCD in the conformal window as a laboratory for unparticle physics, and analyze couplings between the unparticle sector and the Higgs sector. These couplings can lead to the unparticle sector being pushed away from its scale invariant fixed point. We show that this implies that low energy experiments will not be able to see unparticle physics, and the best hope of seeing unparticles is in high energy collider experiments such as the Tevatron and the LHC. We also demonstrate how the breaking of scale invariance could be observed at these experiments.
We study the contribution of the antisymmetric tensor unparticle mediation to the diphoton production rate of the Higgs boson and try to explain the discrepancy between the measured value of the decay width of the discovered new resonance and that of the standard model Higgs boson. We observe that tree level contribution of the antisymmetric unparticle mediation is a possible candidate to explain the measured value of the diphoton decay rate.
Motivated by slow-roll inflationary cosmology we study a scalar unparticle weakly coupled to a Higgs field in the broken symmetry phase. The mixing between the unparticle and the Higgs field results in a seesaw type matrix and the mixing angles feature a Mikheyev-Smirnov-Wolfenstein (MSW) effect as a consequence of the unparticle field being noncanonical. We find two (MSW) resonances for small and large spacelike momenta. The unparticlelike mode features a nearly flat potential with spinodal instabilities and a large expectation value. An effective potential for the unparticlelike field is gen…
A renormalizable coupling between the Higgs and a scalar unparticle operator O_U of non-integer dimension d_U < 2 gives rise, after electroweak symmetry breaking, to a mass gap in the unparticle continuum and a shift in the original Higgs mass, which can end up above or below the mass gap. We show that, besides the displaced Higgs state, a new isolated state can generically appear in the spectrum near or below the mass gap. Such state (which we call phantom Higgs) is a mixture of Higgs and unparticles and therefore has universally reduced couplings to fermions and gauge bosons. This phenomenon…
We propose a model that introduces a supersymmetric unparticle operator in the minimal supersymmetric Standard Model. We analyze the lowest dimension operator involving an unparticle. This operator behaves as a Standard Model gauge singlet and it introduces a new parameter into the Higgs potential which can provide an alternative way to relax the upper limit on the lightest Higgs boson mass. This operator also introduces several unparticle interactions which can induce a neutral Higgsino to decay into a spinor unparticle. It also induces violation of scale invariance around the electroweak sca…
We construct a model of an unparticle sector consisting of a supersymmetric SU(N) gauge theory with the number of flavors in the Seiberg conformal window. We couple this sector to the MSSM via heavy messengers. The resulting low energy theory has a Higgs coupling to unparticles. The Higgs vev drives the hidden Seiberg sector to a new conformal fixed point. The coupling to the Higgs mediates supersymmetry breaking to the Seiberg sector, and breaks conformal invariance at a lower scale. The low energy theory contains light stable and metastable mesons. Higgs decay into this sector gives signatur…
We predict the branching ratios of the lepton flavor violating Higgs decays H^0\rightarrow e^{\pm} μ^{\pm}, H^0\rightarrow e^{\pm} τ^{\pm} and H^0\rightarrow μ^{\pm} τ^{\pm} with the assumption that lepton flavor violation is due to the unparticle mediation. Here, we consider an effective interaction which breaks the conformal invariance after the electroweak symmetry breaking and causes that unparticle becomes massive. The new interaction results in a modification of the mediating unparticle propagator and brings additional contribution to the branching ratios of the lepton flavor violating d…
We predict the branching ratios of the lepton flavor violating Higgs decays H^0->e^{\pm} μ^{\pm}, H^0-> e^{\pm} τ^{\pm} and H^0->μ^{\pm} τ^{\pm} in the case that the lepton flavor violation is carried by the scalar unparticle mediation. We observe that their branching ratios are strongly sensitive to the unparticle scaling dimension and they can reach to the values of the order of $10^{-4}$, for the heavy lepton flavor case and for the small values of the scaling dimension.
An attempt is made to present the influence of the scalar unparticle on some scattering processes in the Randall - Sundum model. The contribution of the scalar unparticle on the production of Higgs - radion at high energy colliders is studied in detail. We evaluate the production cross-sections in the electron-positron ($e^{+}e^{-}$), photon-photon ($γγ$) and gluon-gluon ($gg$) collisions, which depend strongly on the collision energy $\sqrt{s}$, the scaling dimension $d_{U}$ of the unparticle operator $\mathcal{O}_{U}$ and the energy scale $Λ_{U}$. Numerical evaluation shows that the cross - …
We study the possible annihilation cross section of scalar dark matter and its coupling λ_D to the standard model Higgs in the case of the electroweak symmetry breaking driven by unparticle. Here the annihilation process occurs with the help of three intermediate scalars which appear after the mixing. By respecting the annihilation rate which is compatible with the current relic density we predict the tree level coupling λ_D. We observe that the unparticle scaling d_u plays a considerable role on the annihilation process and, therefore, on the coupling λ_D.
Recently, conceptually new physics beyond the Standard Model has been proposed by Georgi, where a new physics sector becomes conformal and provides "unparticle" which couples to the Standard Model sector through higher dimensional operators in low energy effective theory. Among several possibilities, we focus on operators involving the (scalar) unparticle, Higgs and the gauge bosons. Once the Higgs develops the vacuum expectation value (VEV), the conformal symmetry is broken and as a result, the mixing between the unparticle and the Higgs boson emerges. In this paper, we consider the unparticl…
Recently, conceptually new physics beyond the Standard Model has been proposed by Georgi, where a new physics sector becomes conformal and provides "unparticle" which couples to the Standard Model sector through higher dimensional operators in low energy effective theory. Among several possibilities, we focus on operators involving the (scalar) unparticle, Higgs and the gauge bosons. Once the Higgs develops the vacuum expectation value (VEV), the conformal symmetry is broken and as a result, the mixing between the unparticle and the Higgs boson emerges. In this paper, we consider a natural rea…
Recently, conceptually new physics beyond the Standard Model has been proposed, where a hidden conformal sector provides ``unparticle'' which couples to the Standard Model sector through higher dimensional operators in low energy effective theory. Among several possibilities, we focus on operators involving unparticle, the Higgs doublet and the gauge bosons. Once the Higgs doublet develops the vacuum expectation value, the conformal symmetry is broken and as a result, the mixing between unparticle and Higgs boson emerges. We find that this mixing can cause sizable shifts for the couplings betw…
We investigate a scalar potential inspired by the unparticle sector for the electroweak symmetry breaking. The scalar potential contains the interaction between the standard model fields and unparticle sector. It is described by the non-integral power of fields that originates from the nontrivial scaling dimension of the unparticle operator. It is found that the electroweak symmetry is broken at tree level when the interaction is turned on. The scale invariance of unparticle sector is also broken simultaneously, resulting in a physical Higgs and a new lighter scalar particle.
We study the the electroweak symmetry breaking induced by the interaction of unparticles and the SM Higgs with an additional complex scalar. Furthermore, we estimate the contribution of the mixing scalars on the muon anomalous magnetic moment. We observe that this contribution is at least two order less than the discrepancy between the experimental and the SM results of the muon anomalous magnetic moment.
Once a parity is introduced in unparticle physics, under which unparticle provided in a hidden conformal sector is odd while all Standard Model particles are even, unparticle can be a suitable candidate for the cold dark matter (CDM) in the present universe through its coupling to the Standard Model Higgs doublet. We find that for Higgs boson mass in the range, 114.4 GeV < m_h < 250 GeV, the relic abundance of unparticle with mass 50 GeV < m_U < 80 GeV can be consistent with the currently observed CDM density. In this scenario, Higgs boson with mass m_h < 160 GeV dominantly decays into a pair …
We consider scale invariant theories of continuous mass fields, and show how interactions of these fields with the standard model can reproduce unparticle interactions. There is no fixed point or dimensional transmutation involved in this approach. We generalize interactions of the standard model to multiple unparticles in this formalism and explicitly work out some examples, in particular we show that the product of two scalar unparticles behaves as a normalized scalar unparticle with dimension equal to the sum of the two composite unparticle dimensions. Extending the formalism to scale invar…
A new type of scalar potential inspired by unparticles is proposed for the electroweak symmetry breaking. The interaction between the standard model fields and unparticle sector is described by the non-integral power of fields that originates from the nontrivial scaling dimension of the unparticle operator. We find that unlike the usual integral-power potential, the electroweak symmetry is broken at tree level. The scale invariance of unparticle sector is also broken simultaneously, resulting in a physical Higgs and a lighter scalar particle.
The existence of an unparticle sector, weakly coupled to the standard model, would have a profound impact on supernova (SN) physics. Emission of energy into the unparticle sector from the core of SN1987A would have significantly shortened the observed neutrino burst. The unparticle interaction with nucleons, neutrinos, electrons and muons is constrained to be so weak that it is unlikely to provide any missing-energy signature at colliders. One important exception are models where scale invariance in the hidden sector is broken by the Higgs vacuum expectation value. In this case the SN emission…
Coupling the scale invariant unparticle sector to flavour physics and assuming that it remains scale invariant we investigate its consequences in heavy flavour physics. A drastic feature of unparticle physics is an unusual phase leading to novel CP violating phenomena. We consider the CP asymmetry in the leptonic decay B^+ -> tau^+ nu and the hadronic decay B_d -> D^+D^-, taking into account constraints of branching ratios and time dependent CP asymmetries. Generic plots are shown and it turns out that there exist parameters for which the CP violation is maximal. A prediction of a large CP asy…
We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on the coupling and mass parameters originating at a compositeness scale. The phenomenology of this model is discussed including the collider phenomenology at LHC and ILC.
In this talk, we report unitarity constraints and phenomenological studies at the Large Hadron Collider for the extra Higgs bosons of a Composite 2-Higgs Doublet Model.
One of the solutions to the hierarchy problem of the Standard Model is the composite Higgs scenario, where the Higgs emerges as a composite pseudo-Nambu-Goldstone boson. In this work we present and study the basic characteristics of the composite Higgs scenario, based on the $SO(5)/SO(4)$ and $SO(6)/SO(5)$ cosets. We construct their effective Lagrangians through the Callan-Coleman-Wess-Zumino construction. The first coset does not differ much from the Standard Model and the second contains a singlet scalar in addition to the Higgs doublet. In these models we study the gauge sector, the fermion…
We match the electroweak chiral Lagrangian with two singlet scalars to the next-to-minimal composite Higgs model with $ SO(6)/SO(5) $ coset structure and extract the scalar divergences to one loop. Assuming the additional scalar to be heavy, we integrate it out and perform a matching to the well-established electroweak chiral Lagrangian with one light Higgs.
In composite Higgs models light fermionic top partners often play an important role in obtaining a 126 GeV Higgs mass. The presence of these top partners implies that coloured vector mesons, or massive gluon partners, most likely exist. Since the coupling between the top partners and gluon partners can be large there are then sizeable two-loop contributions to the composite Higgs mass. We compute the radiative correction to the Higgs mass from a gluon partner in the minimal composite Higgs model and show that the Higgs mass is in fact reduced. This allows the top partner masses to be increased…
If the Higgs boson is composite, signs of this compositeness should appear via a formfactor-like suppression of Higgs scattering cross sections at momentum transfers above the compositeness scale. We explore this by computing the cross section for e+e- ---> ZH (Higgsstrahlung) in a warped five-dimensional gauge-Higgs unification model known as the Minimal Composite Higgs Model (MCHM). We observe that the Higgsstrahlung cross section in the MCHM is strongly suppressed compared to that in the Standard Model at center-of-mass energies above the scale of the first Kaluza-Klein excitations, due to …
Composite Higgs models provide an attractive solution to the hierarchy problem. However, many realistic models suffer from tuning problems in the Higgs potential. There are often large contributions from the UV dynamics of the composite resonances to the Higgs potential, and tuning between the quadratic term and the quartic term is required to separate the electroweak breaking scale and the compositeness scale. We consider a composite Higgs model based on the $SU(6)/Sp(6)$ coset, where an enhanced symmetry on the fermion resonances can minimize the Higgs quadratic term. Moreover, a Higgs quart…
We explore the Higgs couplings to gauge bosons in the minimal $SO(5)/SO(4)$ 4D composite Higgs model. The pions scatterings put unitary constraints on the couplings and therefore determine the branch ratios of various Higgs decays. Through fine tuning the parameters, enhancement of Higgs to diphoton rate is possible to be achieved with the existence of vector meson fields.
In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type attractive four-fermion interactions, which can break electroweak symmetry dynamically with accompanying composite Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on …
In this note we analyse the prospects of a future electron-positron collider in testing a particular realisation of a composite Higgs model encompassing partial compositeness, namely, the 4-Dimensional Composite Higgs Model. We study the main Higgs production channels for three possible energy stages and different luminosity options of such a machine and confront our results to the expected experimental accuracies in the various Higgs decay channels accessible herein and, for comparison, also at the Large Hadron Collider.
The composite Higgs scenario, in which the Higgs emerges as a composite pseudo-Nambu-Goldstone boson, is extensively reviewed in these Notes. The material is presented in a pedagogical fashion, with great emphasis on the conceptual and technical foundations of the construction. A comprehensive summary of the flavor, collider and electroweak precision phenomenology is also presented.
In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type attractive four-fermion interactions, which can break electroweak symmetry dynamically with accompanying composite Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs sector is a partially composite two-Higgs doublet model with specific boundary conditions on …
In the context of Composite Higgs Models we consider the realisation of an extended Higgs sector with two Higgs doublets arising as pseudo Nambu-Goldstone bosons from a $\textrm{SO}(6) \to \textrm{SO}(4) \times \textrm{SO}(2)$ breaking. The properties of the Higgses are obtained in terms of the fundamental parameters of the composite sector, such as masses, Yukawa and gauge couplings of the new spin-1/2 and spin-1 resonances. After computing the Higgs potential from the explicit breaking of the $\textrm{SO}(6)$ global symmetry by the partial compositeness of fermions and gauge bosons, the main…
In composite Higgs models the Higgs boson arises as a pseudo-Goldstone boson from a strongly-interacting sector. Fermion mass generation is possible through partial compositeness accompanied by the appearance of new heavy fermionic resonances. The Higgs couplings to the Standard Model (SM) particles and between the Higgs bosons themselves are modified with respect to the SM. Higgs pair production is sensitive to the trilinear Higgs self-coupling but also to anomalous couplings like the novel 2-Higgs-2-fermion coupling emerging in composite Higgs models. The QCD corrections to SM Higgs boson pa…
We present a new class of composite Higgs models where an adjustable tree-level Higgs quartic coupling allows for a significant reduction in the tuning of the Higgs potential. Our 5D warped space implementation is the first example of a holographic composite Higgs model with a tree-level quartic. It is inspired by a 6D model where the quartic originates from the Tr [A_5,A_6]^2 term of the gauge field strength, the same model that led to the original little Higgs construction of Arkani-Hamed, Cohen, and Georgi. Beyond the reduction of the tuning and the standard composite Higgs signatures, the …
Composite Higgs models involving partial compositeness of Standard Model fermions typically require the introduction of fermionic partners which are relatively light in realistic scenarios. In this paper, we analyze the role of these light custodian fermions in the phenomenology of the composite Higgs models and show that they significantly modify couplings of the Higgs field. We focus on the coupling to gluons in particular, which is of central importance for Higgs production at the LHC. We show that this coupling can be increased as well as decreased depending on the SM fermion embedding in …
We explore the Higgs-Z-photon coupling in the Minimal Composite Higgs Model with vector and axial resonances. The electroweak precision measurement, i.e. S and T, is estimated for this model. We calculate the signal strength for Higgs decay into Z-photon and notable enhancement is found in certain EWPT allowed parameter region.
We explore the collider relevance of a charge-radius coupling among light mesons in composite Higgs models. In particular, we focus of a coupling of the photon to the composite Higgs and a composite singlet, arising from isospin violation in the underlying theory. This coupling offers a deep probe of the composite nature of the Higgs mechanism, being sensitive to the electromagnetic and weak isospin structure of its constituents. The main collider effect consists in the production of the Higgs boson in association with a light composite pseudo-scalar. We present an exploratory cut-and-count an…
We consider the scenario where the composite Higgs arising as a pNGB in a two-site model with a non-local term included. Constraints from pion scattering and electroweak precision test are considered. We discuss the effects of composite resonances, in particular the one from composite vector-like fermions, on the oblique parameters. It is noticed that the gluon fusion production of Higgs boson is suppressed with respect to the Standard Model for about $6\%$ after imposing the unitarity and electroweak bounds.
We point out that Higgs rates into gauge bosons can be significantly modified in composite pseudo Nambu--Goldstone boson (pNGB) Higgs models if quarks belonging to the first two generation are relatively composite objects as well. Although the lightness of the latter a priori screen them from the electroweak symmetry breaking sector, we show, in an effective two-site description, that their partners can lead to order one shifts in radiative Higgs couplings to gluons and photons. Moreover, due to the pseudo-Goldstone nature of the Higgs boson, the size of these corrections is completely control…
We test the sensitivity of a future e+e- collider to composite Higgs scenarios encompassing partial compositeness. Besides the detailed study of the Higgs properties, such a machine will have a rich top-quark physics programme mainly in two domains: top property accurate determination at the $t \bar t$ production threshold and search for New Physics with top quarks above it. In both domains, a composite Higgs scenario can manifest itself via sizable deviations in both cross-section and asymmetry observables. Herein we discuss such a possibility using a particular realisation, namely the 4-Dime…
The measurement of the trilinear and quartic Higgs self-couplings is necessary for the reconstruction of the Higgs potential. This way the Higgs mechanism as the origin of electroweak symmetry breaking can be tested. The couplings are accessible in multi-Higgs production processes at the LHC. In this paper we investigate the prospects of measuring the trilinear Higgs coupling in composite Higgs models. In these models, the Higgs boson emerges as a pseudo-Goldstone boson of a strongly interacting sector, and the Higgs potential is generated by loops of the Standard Model (SM) gauge bosons and f…
A complete parton level analysis of ll + four jets l = e,mu and 3lv + two jets production at the LHC is presented, including all processes at order $\ordEW$, $\ordQCD$ and $\ordQCDsq$ when appropriate. The infinite Higgs mass scenario, which is considered as a benchmark for strong scattering theories and is the limiting case for composite Higgs models, and one example of a model incorporating a Strongly Interacting Light Higgs are confronted with the Standard Model light Higgs predictions. This analysis is combined with the results in the lv + four jets channel presented in a previous paper, i…
We explain general features of the tightly bound composite Higgs models proposed in recent years; walking technicolor, strong ETC technicolor, and a top quark condensate, etc.. These models are all characterized by the large anomalous dimension due to nontrivial short distance dynamics in the gauged Nambu-Jona-Lasinio models (gauge theories plus four-fermion interactions).
Composite Higgs models are only now starting to be probed at the Large Hadron Collider by Higgs searches. We point out that new resonances, abundant in these models, can mediate new production mechanisms for the composite Higgs. The new channels involve the exchange of a massive color octet and single production of new fermion resonances with subsequent decays into the Higgs and a Standard Model quark. The sizable cross section and very distinctive kinematics allow for a very clean extraction of the signal over the background with high statistical significance. Heavy gluon masses up to 2.8 TeV…
We study the Higgs mass in composite Higgs models with partial compositeness, extending the results of Ref. [1] to different representations of the composite sector for SO(5)/SO(4) and to the coset SO(6)/SO(5). For a given tuning we find in general a strong correlation between the mass of the top partners and the Higgs mass, akin to the one in supersymmetry. If the theory is natural a Higgs mass of 125 GeV typically requires fermionic partners below TeV which might be within the reach of the present run of LHC. A discussion of CP properties of both cosets is also presented.
The radial excitation of the global symmetry-breaking vacuum in composite Higgs models, called the "global Higgs", has been recently a focus of investigation. In this paper we study the prospects for detecting this composite scalar at the 13 TeV LHC. We compute the global Higgs production rates and estimate the discovery potential of a global Higgs decaying into top quark pairs and into Higgs and electroweak gauge bosons with subsequent hadronic decays. The global Higgs may also decay into fermion resonances such as top partners, providing a new window into compositeness. We show that top part…
We present an overview of composite Higgs models in light of the discovery of the Higgs boson. The small value of the physical Higgs mass suggests that the Higgs quartic is likely loop generated, thus models with tree-level quartics will generically be more tuned. We classify the various models (including bona fide composite Higgs, little Higgs, holographic composite Higgs, twin Higgs and dilatonic Higgs) based on their predictions for the Higgs potential, review the basic ingredients of each of them, and quantify the amount of tuning needed, which is not negligible in any model. We explain th…
We consider a Composite Higgs Model (CHM) with two isospin doublet Higgs fields arising as pseudo Nambu-Goldstone bosons from a ${\rm SO}(6)\to {\rm SO}(4)\times {\rm SO}(2)$ breaking. The main focus of this work is to explicitly compute the properties of these Higgses in terms of the fundamental parameters of the composite sector such as masses, Yukawa and gauge couplings of the new spin-1 and spin-1/2 resonances. Concretely, we calculate the Higgs potential at one-loop level through the Coleman-Weinberg mechanism from the explicit breaking of the ${\rm SO(6)}$ global symmetry by the partial …
Composite Higgs and neutral-naturalness models are popular scenarios in which the Higgs boson is a pseudo Nambu-Goldstone boson, and naturalness problem is addressed by composite top partners. Since the standard model effective field theory (SMEFT) with dimension-six operators cannot fully retain the information of Higgs nonlinearity due to its PNGB nature, we systematically construct low energy Lagrangian in which the information of compositeness and Higgs nonlinearity are encoded in the form factors, the two-point functions in the top sector. We classify naturalness conditions in various sce…
We study the the impact of Run2 LHC data on general Composite Higgs scenarios, where non-linear effects, mixing with additional scalars and new fermionic degrees of freedom could simultaneously contribute to the modification of Higgs properties. We obtain new experimental limits on the scale of compositeness, the mixing with singlets and doublets with the Higgs, and the mass and mixing angle of top-partners. We also show that for scenarios where new fermionic degrees of freedom are involved in electroweak symmetry breaking, there is an interesting interplay among Higgs coupling measurements, b…
We study a new confining gauge theory with fermions in a vectorial representation under the SM gauge group that allows for Yukawa interactions with the Higgs. If the fermion masses are smaller than the confinement scale this realizes a type I two Higgs doublet model where a composite Higgs mixes with the elementary Higgs. This class of models interpolates between an elementary and a composite Higgs and has interesting phenomenology with potentially observables effects in collider physics, EDMs and SM couplings but very weak bounds from indirect searches. The very same framework can be used to …
In the composite Higgs models, originally proposed by Georgi and Kaplan, the Higgs boson is a pseudo Nambu-Goldstone boson (pNGB) of spontaneous breaking of a global symmetry. In the minimal version of such models, global SO(5) symmetry is spontaneously broken to SO(4), and the pNGBs form an isospin doublet field, which corresponds to the Higgs doublet in the Standard Model (SM). Predicted coupling constants of the Higgs boson can in general deviate from the SM predictions, depending on the compositeness parameter. The deviation pattern is determined also by the detail of the matter sector. We…
