Radiative corrections in fermion bags bound by Higgs boson exchange
M. Yu. Kuchiev, V. V. Flambaum
备注：
4 pages, 4 figures, references added, dependence of the radiative corrections on the number of heavy fermions contributing to the vacuum polarization is descussed
Radiative corrections for several heavy fermions bound together via the Higgs boson exchange are studied. The fermion bags considered include 12, or fewer, fermions occupying the lowest S_{1/2} shell. It is shown that for `moderately heavy' fermions with masses 0.4< m c^2< 1 TeV the radiative corrections are small, 10^{-2}, and have an attractive nature. Therefore they do not put existence of the fermion bag in doubt. This proves that these fermion bags can exist in nature.
Properties of amplitudes that describe radiative corrections in a bag of heavy fermions bound by the Higgs boson exchange are studied. Classes of amplitudes, in which the large fermion mass is canceled out and hence produces no enhancement for the radiative corrections are found. For fermions with masses in the region 400< m < 1000 Gev all relevant amplitudes are found to possess this property. Correspondingly the radiative corrections for this range of masses are small. For very heavy fermions, m>1000 Gev, the processes described by diagrams with closed fermion loops are also mass-independent…
Recently it has been suggested that top quarks, or very massive fourth generation quarks, might surround themselves with a Higgs "bag" of deformation of the Higgs expectation value from its vacuum magnitude. In this paper we address the question of whether such nonlinear Higgs-top interaction effects are subject to experimental test. We first note that if top quarks were necessarily accompanied by Higgs "bags", then top quark weak decay would involve the sudden disruption of the Higgs "bag", with copious production of physical Higgs particles accompanying the decay. We then examine the effects…
We discuss a new family of multi-quanta bound states in the Standard Model, which exist due to the mutual Higgs-based attraction of the heaviest members of the SM, namely, gauge quanta $W,Z$ and (anti)top quarks, $\bar t, t $. We use a self-consistent mean-field approximation, up to a rather large particle number $N$. In this paper we do not focus on weakly-bound, non-relativistic bound states, but rather on "bags" in which the Higgs VEV is significantly modified/depleted. The minimal number $N$ above which such states appear strongly depends on the ratio of the Higgs mass to the masses of $W,…
We argue that the Standard Model contains stable bound states with a sufficiently large number N of heavy quanta -top quarks and gauge bosons W,Z- of the form of collective "bags", with a strongly depleted value of the Higgs VEV inside. More specifically, we study one-loop quantum corrections to a generic model of them, assuming "quanta" are described by a complex scalar field. We follow the practical formalism developed by Farhi et al. for the N=1 case, i.e. one particle in a bag, who found that for a very large Yukawa coupling the classical bags are destabilized by quantum effects. We instea…
Nontopological solitons, or ``bags,'' can arise when fermions acquire their mass through a Yukawa coupling to some scalar field. Bags have played an important role in models of baryons, nuclei, and more recently, in the idea that a Higgs condensate may form around a very heavy top quark. It has been claimed that deep bags, which correspond to tightly-bound states of fermions, will form when the Yukawa coupling is strong. Quantum corrections, however, are significant in this regime. We examine the effects of these quantum corrections on the formation of nontopological solitons in an exactly sol…
Higgs boson properties could be studied with a high accuracy at a muon collider via the s-channel resonant production. We consider the situation where the center-of-mass energy of the muon collider is off the resonance above the Higgs mass. We discuss the discovery potential for a generic heavy Higgs boson ($H$) and compare different production mechanisms, including the "radiative return" ($γH$), $Z$-boson associated production ($ZH$) and heavy Higgs pair production ($HA$). These production mechanisms do not sensitively rely on a priori knowledge of the heavy Higgs boson mass. We include vario…
The naive fermiophobic scenario is unstable under radiative corrections, due to the chiral-symmetry breaking induced by fermion mass terms. In a recent study, the problem of including the radiative corrections has been tackled via an effective field theory approach. The renormalized Yukawa couplings are assumed to vanish at a high energy scale $Λ$, and their values at the electroweak scale are computed via modified Renormalization Group Equations. We show that, in case a fermiophobic Higgs scenario shows up at the LHC, a linear collider program will be needed to accurately measure the radiativ…
We briefly review the phenomenological implications of the minimal supersymmetric standard model (MSSM) with explicit radiative breaking of CP invariance in the Higgs sector for the LEP2 and Tevatron colliders.
In the framework of the effective field theory approach to heavy supersymmetry radiative corrections in the Higgs sector of the Minimal Supersymmetric Standard Model (MSSM) for the effective potential decomposition up to the dimension-six operators are calculated. Symbolic expressions for the threshold corrections induced by $F$- and $D$- soft supersymmetry breaking terms are derived and the Higgs boson mass spectrum respecting the condition $m_h=$125 GeV for the lightest $CP$-even scalar is evaluated.
Some aspects of the phenomenology of the top quark and the charged Higgs are studied, emphasizing relations due to radiative corrections. Production mechanisms at the SSC are mentioned, and decay modes are analyzed including radiative corrections to the charged Higgs mass and couplings. The constraints due to the decay b-> s γare discussed. Calculations are performed in the context of the Minimal Supersymmetric Model.
The radiative decay width of a heavy Higgs boson $H \rightarrow W^+W^-γ$ for a {\it hard} photon is calculated in the Standard Model and its extension with anomalous $γWW$ couplings. Its dependence on the Higgs mass, the two unknown anomalous couplings, and the photon energy cutoff are studied in detail. We show that this radiative decay of a heavy Higgs is not very sensitive to a wide range of the anomalous couplings compared to the Standard Model result.
We calculate 1-loop radiative corrections to the $hZZ$ and $hWW$ couplings in models with next--to--simplest Higgs sectors satisfying the electroweak $ρ$ parameter equal to 1 at tree level: the Higgs singlet model, the two-Higgs doublet models, and the Georgi-Machacek model. Under theoretical and current experimental constraints, the three models have different correlations between the deviations in the $hZZ$ and $hWW$ couplings from the standard model predictions. In particular, we find for each model predictions with no overlap with the other two models.
The possibility of having relatively large non-decoupling effects of the heavy Higgs particles within the two-Higgs doublet extension of the electroweak standard model is briefly discussed and demonstrated on an example of the one-loop amplitude of the process e^+e^- -> W^+W^-
In twin Higgs model, the Higgs boson mass is protected by a $Z_2$ symmetry. The $Z_2$ symmetry needs to be broken either explicitly or spontaneously to obtain misalignment between electroweak and new physics vacua. We propose a novel $Z_2$ breaking mechanism, in which the $Z_2$ is spontaneously broken by radiative corrections to the Higgs potential. Two twin Higgses with different vacua are needed, and vacuum misalignment is realized by opposite but comparable contributions from gauge and Yukawa interactions to the potential. Due to fully radiative symmetry breaking, the Higgs sector is comple…
Higgs boson mass sum rules of supersymmetric models offer attractive targets for precision tests at future muon colliders. These sum rules involve the gauge boson masses as well as the masses of the Higgs boson states which can be precisely measured in the $s$-channel production process at a muon collider. These measurements can sensitively probe radiative corrections to the Higgs boson masses as well as test for CP-violation and nonminimality of the Higgs sector.
We discuss the large radiative corrections to the masses of supersymmetric Higgs bosons in the MSSM and in its simplest extension, the NMSSM, with particular attention paid to the bounds on the lightest CP-even Higgs mass found in both models. In the case of the MSSM, these corrections are found to be primarily associated with the effects top quark and stop squark loops, while for extended models they also include significant contributions from Higgs and Higgsino loops. (Talk presented at SUSY-93, Boston, March 1993)
In the decoupling limit of a non-minimal Higgs sector, the lightest CP-even Higgs boson (h) is indistinguishable from the Standard Model (SM) Higgs boson. In the two-Higgs-doublet sector of the MSSM, the approach to the decoupling limit (for m_A>>m_Z) persists, even in the presence of potentially large (tan(beta)-enhanced) radiative corrections to the hbb coupling. Radiative corrections can also generate an accidental cancellation between tree-level and one-loop terms, resulting in a SM-like Higgs boson for moderate m_A outside the decoupling regime.
Electroweak radiative corrections are computed for Higgs production through vector boson fusion, qq->qqH, which is one of the most promising channels for detecting and studying the Higgs boson at the LHC. Using soft-collinear effective theory, we obtain numerical results for the resummed logarithmic contributions to the hadronic cross section at next-to-leading logarithmic order. We compare our results to HAWK and find good agreement below 2 TeV where the logarithms do not dominate. The SCET method is at its best in the high LHC energy domain where the corrections are found to be slightly larg…
We discuss the implications of global symmetries on the radiative corrections to the Higgs sector. We focus on two examples: the charged Higgs mass in the minimal supersymmetric model and the Higgs couplings to vector boson pairs. In the first case, we find that in the absence of squark mixing a global SU(2)$\times$SU(2) symmetry protects the charged Higgs mass from corrections of ${\cal O}(g^2m^4_t/m^2_W)$. In the second case, it is the {\it custodial} symmetry which plays an analogous role in constraining the fermion-mass dependence of the radiative corrections.
QCD radiative correction to Higgs $\rightarrow$ two photons decay rate is calculated. Below the threshold we found negligible correction, thus supporting results obtained earlier by Djouadi et all [7]. Above the threshold radiative correction appears to be large for both real and imaginary part of H $γγ$ vertex. This leads to radiative correction for $Γ$(H $\rightarrow γγ$) to be of order 20--100 percents at $m_{t}=150 GeV$. Possible applications of our results for Higgs search at Next Linear Colliders (NLC) are briefly discussed.
The electroweak radiative correction, which turned out to be marginal within the standard electroweak model having the minimal Higgs sector in view of the present experimental information, fits well the experiment when the Higgs sector is extended to have two Higgs doublets. We predict the range where the charged and CP odd Higgs boson masses would lie, taking the two CP even neutral Higgs boson masses to be degenerate which makes the analysis in multiparameter space feasible. It is shown that the mass of neutral Higgs doublet boson can arbitrarily be large consistently with the $W$ mass, if t…
We study the radiative lepton flavor violating l_1->l_2γdecays in the two Higgs doublet model with localized new Higgs doublet in the Randall Sundrum background. We estimate the contributions of the KK modes of new Higgs bosons and left (right) handed charged lepton doublets (singlets) on the branching ratios of the decays considered. We observe that there is an enhancement in the branching ratios with the addition of new Higgs boson and lepton KK modes.
In this work we compute the radiative corrections to the Higgs mass and the Higgs quartic couplings coming from the Higgs sector itself and the scalar fields $ϕ$ in the Littlest Higgs (LH) model. The restrictions that the new contributions set on the parameter space of the models are also discussed. Finally this work, together with our three previous papers, complete our program addressed to compute the relevant contributions to the Higgs low-energy effective potential in the LH model and the analysis of their phenomenological consequences.
We study the NNLO radiative corrections of enhanced electroweak strength to the lineshape of the Higgs boson in the processes ($μ^+μ^- \to H \to ZZ$) and ($μ^+μ^- \to H \to t\bar t$), which are of interest for Higgs searches at a possible muon collider. We give the radiative corrections both in the on-shell renormalization scheme and in the pole renormalization scheme. The pole scheme appears to have better convergence properties, in agreement with previous results regarding the position of the Higgs pole in the complex plane.
The radiative B ->τ^+ τ^- γdecay is investigated in the framework of the two Higgs doublet model . The dependence of the differential branching ratio on the photon energy and the branching ratio on the two Higgs doublet model parameters, m_{H^\pm} and \tan β, are studied. It is shown that there is an enhancement in the predictions of the two Higgs doublet model compared to the Standard model case. We also observe that contributions of neutral Higgs bosons to the decay are sizable when \tanβis large.
We calculate radiative corrections to the masses of the Higgs bosons in a minimal supersymmetric model that contains an additional non-anomalous (U(1)') gauge symmetry. With some fine-tuning of the (U(1)') charges of the Higgs fields, it is possible to suppress the (Z)--(Z^{\prime}) mixing. We use this fact, along with the lower bound on the lightest Higgs mass after LEPII era, as a criterion to restrict the set of parameters in our analysis. We calculate the mass of the lightest Higgs and its mixing with the other Higgs bosons, in a large region of the parameter space.
The mechanism of radiative electroweak symmetry breaking occurs through loop corrections, and unlike conventional symmetry breaking where the Higgs mass is a parameter, the radiatively-generated Higgs mass is dynamically predicted. Pade approximations and an averaging method are developed to extend the Higgs mass predictions in radiative electroweak symmetry breaking from five- to nine-loop order in the scalar sector of the Standard Model, resulting in an upper bound on the Higgs mass of 141 GeV. The mass predictions are well-described by a geometric series behaviour, converging to an asymptot…
The decay rate of a (neutral) Higgs boson ($H$) going into a longitudinal $W$-boson pair is calculated by including one loop radiative corrections in a two-Higgs doublet model. It is assumed that the Higgs boson $H$ is much heavier than the $W$ boson and a full use has been made of the equivalence theorem. A possibility is explored extensively that the precise measurement of the decay rate of $H$ could be useful as a probe of the other neutral as well as charged Higgs bosons through potentially important radiative corrections. It is pointed out that, for some choice of the parameters, the radi…
1-loop diagrammatic calculations of cross sections and decay widths of neutral Higgs bosons in the minimal supersymmetric standard model are reviewed and compared with compact expressions in the effective potential approximation.
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…
We derive analytic formulas for the radiatively corrected mass of the scalar Higgs boson in the framework of the minimal supersymmetric standard model (MSSM). Since the scalar-top-quark mass in our analysis include terms proportional to the gauge couplings in the 1-loop effective potential, the radiatively corrected mass of the scalar Higgs boson partially contains the gauge boson contributions. At the 1-loop level, the upper bound on the lighter scalar Higgs boson mass can be increased about 20 GeV in favor of the partial contributions of the gauge bosons. Thus the improved absolute upper bou…
Neutral Higgs boson radiative decays of the form h_0, H, A \to f\bar{f}γ, in the light fermion limit $m_f->0, are calculated in the two Higgs doublet model at one-loop level. Comparisons with the calculation within the standard model are given, which indicates that these two models are distinguishable in the decay mode fermion-antifermion -photon. Our results show that the concerned process may stand as an implement to identify the Higgs belongings in case there is a intermediate mass Higgs detected.
We discuss the feasibility of spontaneous CP violation being induced by radiative corrections in 2HDM's. Specifically, we analyze the cases of gaugino/higgsino effect on MSSM, and a new model with an extra exotic quark doublet. The new model, while demonstrating well the Georgi-Pais theorem, is also expected to be phenomenlogically interesting.
Higgs boson radiative decays of the form $H\rightarrow f\bar{f}γ$ are calculated in the Standard Model using the complete one-loop expressions for the decay amplitudes. Contributions to the radiative width from leptons and light quarks are given. We also present $e\bar{e}$ invariant mass distributions for $H\rightarrow e\bar{e}γ$, which illustrate the importance of the photon pole contribution and the effects of the box diagrams.
We have investigated in detail a model that contains an additional SU(2) singlet and triplet scalar fields than the Standard Model (SM). This allows the radiative generation of Majorana neutrino masses at two-loop order with the help of doubly charged Higgs bosons that arise from the extended Higgs sector. We studied in detail the phenomenology of the Higgs and neutrino sectors of the model. We give the analytical form of the masses of scalar and pseudoscalar bosons and their mixings, and the structure of the active neutrino mass matrix. It is found that the model accommodates only normal neut…
The possible existence of a light CP-odd Higgs state in many new-physics models could lead to observable effects in the bottomonium sector. Experimental bounds on radiative $Υ$ decays through such a pseudoscalar state and possible mixings with the $η_b^0$ states are reviewed. Combining these two effects, we set constraints on the properties of the CP-odd Higgs in the limit of small photon energy of $BR(Υ\toγ\,τ^+τ^-)$, that is on the pseudoscalar mass-range $\sim8-10$GeV.
This note is devoted to the calculation of the two-loop $O(G_F {M_H}^2)$ radiative corrections to the Higgs decay width $H \to γγ$ for large values of the Higgs boson mass $M_H$ within the Minimal Standard Model. The use of the Equivalence Theorem makes it possible to reduce the problem to the consideration of the physical Higgs boson field and the Goldstone bosons $w^{+},w^{-},z$. We present analytical results for the various two- and three-particle absorptive parts of two-loop contributions, using dispersive techniques, analytic results for all but one of the dispersive contributions. The ty…
The one-loop radiative corrections to the Higgs boson potential in the MSSM, originating from the top quark and squark loops, are summed in the leading log approximation using the renormalization group. The RG improved effective potential is minimized and the corrections to the CP-odd and CP-even Higgs boson masses are calculated. The resulting masses exhibit smoother top mass dependence than those calculated without RG summation. We have also found that for preferable values of the top mass the light Higgs mass does not exceed 100 GeV.
We study possible effects of a light CP-odd Higgs boson on radiative Upsilon decays in the Next-to-Minimal Supersymmetric Standard Model. Recent constraints from CLEO on radiative Upsilon(1S) decays are translated into constraints on the parameter space of CP-odd Higgs boson masses and couplings, and compared to constraints from B physics and the muon anomalous magnetic moment. Possible Higgs - eta_b(nS) mixing effects are discussed, notably in the light of the recent measurement of the eta_b(1S) mass by Babar: The somewhat large Upsilon(1S) - eta_b(1S) hyperfine splitting could easily be expl…
Starting from the unmixed Lagrangian, the electro-weak radiative corrections are recomputed using symmetrical generalised functions. All gauge bosons acquire an indeterminate mass. Electro-weak mixing is obtained by diagonalization of the mass matrix. The W/Z mass ratio follows automatically. The Higgs mechanism is not needed to generate the vector boson masses. A mass sum rule is postulated to obtain a zero photon mass. The radiative corrections are different, and (provisionally) in agreement with experiment, when the no longer needed Higgs terms are omitted.
Using a $SU(4)\rightarrow Sp(4)$ pattern of chiral symmetry breaking, we investigate the pseudo-Goldstone nature of the Higgs boson in an elementary realisation that at the same time provides an ultraviolet completion. The renormalizability of the model together with the perturbative corrections determine dynamically the direction of vacuum of the theory and the corresponding Higgs chiral symmetry breaking scale $ f \sim 14~$TeV. The Higgs boson is radiatively generated and the scalar mass spectrum, together with a second massive Higgs boson, lie in the multi-TeV range.
We review the mechanism of radiative electroweak symmetry breaking taking place in SUSY versions of the standard model. We further discuss different proposals for the origin of SUSY-breaking and the corresponding induced SUSY-breaking soft terms. Several proposals for the understanding of the little hierarchy problem are critically discussed.
We evaluate dominant two-loop corrections to the triple Higgs coupling and strength of a first-order electroweak phase transition in the inert Higgs doublet model. It is found that sunset diagrams can predominantly enhance the former and reduce the latter. As a result, the triple Higgs coupling normalized by the standard model value at two-loop level is more enhanced than the corresponding one-loop value.
A collider probe of the radiative seesaw models are considered. Two key ingredients of these models, the extended Higgs sector and the source of the Majorana mass, although these details differ model by model, would be studied at the TeV-scale electron-positron and electron-electron colliders. The searches and mass determinations in the inert doublet model, which is the extended Higgs sector of the Ma model, are summarized as an example.
The radiative corrections to the $3\times3$scalar and the $2\times2$ pseudoscalar neutral Higgs boson massmatrices are calculated in the supersymmetric extension of the standard model including a gauge singlet superfield in the effective potential approach. The full $t$ and $b$ quark/squark contributions including the nonlogarithmic terms are taken into account, which are seen to affect the result significantly. An analytic formula for the upper bound on the mass of the lightest neutral Higgs scalar including these corrections is given. (Figure available upon request)
We explore the radiative corrections to the process Z --> b b-bar in models with extended Higgs sectors. The observables R_b (the Z hadronic branching fraction to b b-bar) and the b-quark asymmetry A_b = (g_L^2 - g_R^2)/(g_L^2 + g_R^2) are sensitive to these corrections. We find that in models containing only Higgs doublets, singlets, or larger multiplets constrained by a custodial SU(2) symmetry, the radiative corrections to R_b involving charged Higgs bosons always worsen the Standard Model fit to electroweak data. Thus, the present R_b data can be used to set lower bounds on the charged Hig…
We compute the leading logarithmic radiative corrections to the lightest Higgs mass in the NMSSM involving the electroweak gauge couplings and in the NMSSM specific Yukawa couplings lambda and kappa (including all mixed combinations), which are induced by chargino, neutralino and Higgs boson loops. The effect of the NMSSM specific Yukawa couplings lambda and kappa is to increase the upper bound on the lightest Higgs mass by up to ~2 GeV, but they can also decrease the lightest Higgs mass by up to ~-20 GeV.
The Higgs sector of the Standard Model with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.
The one-loop radiative correction in an ultraviolet (UV) complete electroweak (EW) model without a Higgs particle is calculated. The $ρ$ parameter determining the ratio of the charged to neutral currents is derived for the dominant top quark contribution with the result $ρ\sim 1.01$. This result is compared to the radiative correction to $ρ$ in the standard EW model with a Higgs particle. For the favored light Higgs particle mass from global fits to EW data: $114.4\,{\rm GeV} \leq m_H\leq 135\, {\rm GeV}$, the Higgs contribution up to three loops is negligible and the Higgless model is consist…
In the standard model (SM), lepton flavor violating (LFV) Higgs decay is absent at renormalizable level and thus it is a good probe to new physics. In this article we study a type of new physics that could lead to large LFV Higgs decay, i.e., a lepton-flavored dark matter (DM) model which is specified by a Majorana DM and scalar lepton mediators. Different from other similar models with similar setup, we introduce both left-handed and right-handed scalar leptons. They allow large LFV Higgs decay and thus may explain the tentative Br$(h\raτμ)\sim1\%$ experimental results from the LHC. In partic…
We perform a systematic study of radiative corrections to the masses of the Higgs bosons in the minimal supersymmetric standard model (MSSM) augmented by a single gauge singlet, the so-called next-to-minimal supersymmetric standard model (NMSSM). Our method is based on the one-loop effective potential and includes effects of top quark, squark, Higgs and Higgsino loops. We discuss the renormalisation group flows of Yukawa couplings and the upper bound on the lightest CP-even neutral Higgs boson mass as a function of the heavier stop mass and top mass. We then give a general discussion of Higgs …
The radiative leptonic $B_{c}\toτ\bar{ν_τ}γ$ decay is analysed in context of 2HDM. It is shown that with large values of $tanβ$, the contributions of Model II to the decay rate exceeds considerably the Standard Model ones, while the contributions of Model I overlap with the Standard Model predictions.
We compute radiative correction to the lightest neutral Higgs mass ($m_h$) induced by the Kaluza-Klein (KK) towers of fermions and sfermions in a minimal supersymmetric scenario embeded in a 5-dimensional warped space. The Higgs is confined to the TeV brane. The KK spectra of matter supermultiplets is tied to the explanation of the fermion mass hierarchy problem. We demonstrate that for a reasonable choice of extra-dimensional parameters, the KK-induced radiative correction can enhance the upper limit on $m_h$ by as much as 100 GeV beyond the 4d limit of 135 GeV.
We show that charged-lepton masses can be radiatively induced in multi-Higgs doublet models (NHDMs) through the renormalization group running of Yukawa couplings from high to low energies. Some extreme examples of electron and muon mass generation are discussed in the context of two and three Higgs doublet models. It is also shown that quantum corrections to the Yukawa couplings can be naturally of the same order as the tree-level values. We also comment on the implications of considering extensions of NHDMs in which right-handed neutrinos are added.
We investigate the implication of the recent discovery of a Higgs-like particle in the first phase of the LHC Run 1 on the Inert Higgs Doublet Model (IHDM). The determination of the Higgs couplings to SM particles and its intrinsic properties will get improved during the new LHC Run 2 starting this year. The new LHC Run 2 would also shade some light on the triple Higgs coupling. Such measurement is very important in order to establish the details of the electroweak symmetry breaking mechanism. Given the importance of the Higgs couplings both at the LHC and $e^+e^-$ Linear Collider machines, ac…
We study the radiative h^0 (A^0)\to γγdecays in the framework of the general two Higgs doublet model, the so-called model III. We estimate the decay width of the processes at the order of magnitude of 10^{-2} GeV for the intermediate values of the Yukawa couplings. We observe that the analysis of the two photon system provide a comprehensive information for the complex nature of the Yukawa couplings and therefore, the source of the CP violation.
The recent discovery of the Higgs-like resonance at $125\,\rm{GeV}$ has opened up new avenues in the search for beyond standard model physics. Hints of such extensions could manifest themselves as modifications in the Higgs-fermion couplings and other Higgs related observables. In this work, we study aspects of a class of models where the light fermion masses are radiatively generated. Specifically, we consider models where the light fermion masses, partially or completely, arise from chiral violation in the soft supersymmetry-breaking sector. In these models, the radiatively generated Higgs-f…
We compute the one-loop corrections to the triple Higgs self-interaction $hhh$ in the framework of the Standard Model (SM), the Two Higgs Doublet Model type III (THDM-III) and the Littlest Higgs Model with T parity (LHBM+T). Our results are compared with previous results for the SM. In particular, we find that an imaginary part for the $λ_{hhh}$ form factor is induced when one of the Higgs boson legs is off-mass shell with 4-momentum magnitude higher than the Higgs boson mass. This contribution is sensitive to virtual effects of the Higgs self-interaction, that induces a radiative correction t…
The neutral Higgs sector of the Minimal non Minimal Supersymmetric Standard Model is considered. By effective potential and R.G.E. supported method; an upper bound of the lightest Higgs is analysed. From the request of perturbativity of the coupling in the superpotential, adding the leading stop top contributions, the absolute bound of $\sim 130$ GeV for $90 GeV < m_t< 180 GeV$ and $M_{\tilde{t}} \simeq 1000 $ GeV is derived. The interesting dependence on $m_t$ for $\tanβ \to 1$ is discussed .
We calculate radiative corrections to decay rates of CP-odd Higgs boson $A$ for various decay modes in the four types of two Higgs doublet models with the softly broken discrete $Z_{2}$ symmetry. The decay branching ratios are evaluated at the next-to-leading order for electroweak corrections and the next-to-next-to-leading order for QCD corrections. We comprehensively study the impact of the electroweak corrections on the decay rates and the branching ratios. We find that the radiative corrections can sizably modify the branching ratios, especially for the $A\to Zh$ decay mode in the nearly a…
