We propose that the leptonic cosmic ray signals seen by PAMELA and ATIC result from the annihilation or decay of dark matter particles via states of a leptonic Higgs doublet to $τ$ leptons, linking cosmic ray signals of dark matter to LHC signals of the Higgs sector. The states of the leptonic Higgs doublet are lighter than about 200 GeV, yielding large $\barτ τ$ and $\barτ τ\barτ τ$ event rates at the LHC. Simple models are given for the dark matter particle and its interactions with the leptonic Higgs, for cosmic ray signals arising from both annihilations and decays in the galactic halo. For the case of annihilations, cosmic photon and neutrino signals are on the verge of discovery.
We explore the consequences of the Higgs fields acting as messengers of supersymmetry breaking. The hidden-sector paradigm in the gauge mediation framework is relaxed by allowing two types of gauge-invariant, renormalizable operators that are typically discarded: direct coupling between the Higgses and supersymmetry breaking singlets, and Higgs-messenger mixing terms. The most important phenomenological consequence is a flavor-dependent shift in sfermion masses. This is from a one-loop contribution, which we compute for a general set of weak doublet messengers. We also study a couple of explic…
In this paper, we investigate the phenomenologies of models where the Higgs sector plays the role of messengers in gauge mediation. The minimal Higgs sector and its extension are considered respectively. We find that there exist viable models when an appropriate parity is imposed. Phenomenological features in these kind of models include three sum rules for scalar masses, light gluino as well as one-loop $μ$ and two-loop $Bμ$ terms.
The lighter neutral scalar Higgs mass is examined in gauge-mediated supersymmetry-breaking models in which the messenger sector responsible for SUSY breaking is allowed to involve more general sets of $SU(3) \otimes SU(2) \otimes U(1)$ multiplets than those contained in the SU(5) $5 + \bar{5}$ or $10 + \bar{10}$ multiplets. The largest mass for the lighter scalar Higgs is found to be 132 GeV when the breaking parameter $Λ$ is taken to be 100 TeV\@. Thus the predictions for the lightest Higgs mass can be tested at the upgraded Tevatron runs for these general classes of GMSB models.
The discovery of the Higgs particle at 125 GeV has put strong constraints on minimal messenger models of gauge mediation, pushing the stop masses into the multi-TeV regime. Extensions of these models with matter-messenger mixing terms have been proposed to generate a large trilinear parameter, $A_t$, relaxing these constraints. The detailed survey of these models \cite{Byakti:2013ti,Evans:2013kxa} so far considered messenger mixings with only MSSM superfields. In the present work, we extend the survey to MSSM with inverse-seesaw mechanism. The neutrino-sneutrino corrections to the Higgs mass i…
A 125 GeV Higgs renders the simpler GMSB models unnatural, essentially pushing the soft spectrum beyond the LHC reach. A direct coupling of the matter and messenger fields, that facilitates an enhanced mixing in the squark sector, is a way to ameliorate this deficiency. We construct all possible messenger-matter interaction terms considering the messenger multiplets in 1, 5 and 10 dimensional representations of the SU(5). A Froggatt-Nielsen like flavor framework connected with the origin of fermion mass hierarchy is utilized to control the interaction terms and suppress FCNC. We perform a deta…
We explore the model-building and phenomenology of flavored gauge mediation models of supersymmetry breaking in which the electroweak Higgs doublets and the SU(2) messenger doublets are connected by a discrete non-Abelian symmetry. The embedding of the Higgs and messenger fields into representations of this non-Abelian Higgs-messenger symmetry results in specific relations between the Standard Model Yukawa couplings and the messenger-matter Yukawa interactions. Taking the concrete example of an S(3) Higgs-messenger symmetry, we demonstrate that while the minimal implementation of this scenario…
Almost degenerate bino and wino masses at the weak scale is one of unique features of gauge messenger models. The lightest neutralino is a mixture of bino, wino and higgsino and can produce the correct amount of the dark matter density if it is the lightest supersymmetric particle. Furthermore, as a result of squeezed spectrum of superpartners which is typical for gauge messenger models, various co-annihilation and resonance regions overlap and very often the correct amount of the neutralino relic density is generated as an interplay of several processes. This feature makes the explanation of …
We summarized our report on leptonic flavor violating Higgs decay into mu + tau under the scheme of a generic supersymmetric standard model without R parity. With known experimental constraints imposed, important combinations of R-parity violating parameters which can give notable branching ratios are listed.
Leptonic decays of vector-states of bottomonium are analized searching for a light pseudoscalar Higgs-like neutral boson manifesting via an apparent breaking of lepton universality.
We analyze a minimal flavored gauge mediation model in which the electroweak Higgs and messenger doublets are embedded in multiplets of a discrete non-Abelian symmetry. In this scenario, the minimal Higgs-messenger sector that is consistent with the 125 GeV Higgs mass has two vectorlike pairs of messenger fields. This scenario is obtained in a specific limit of the superpotential interactions of the Higgs-messenger fields and the matter fields. Due to the structure of the messenger-matter Yukawa couplings in this limit, sizable stop mixing and flavor-diagonal soft supersymmetry breaking parame…
A leptonic $(\bar l l)$ decay of a heavy quark-antiquark bound state $T(\bar QQ)$ with a Higgs-boson $H$ emission is investigated. The applying of the well-known low-energy theorem to meson-Higgs coupling allows one to estimate the probability of the decay $T(\bar QQ)\to \bar ll H$. The only a simple version of the Standard Model extension containing two-Higgs doublet is considered.
This is a short review of the framework proposed in \cite{Goh:2009wg} which gives rise to indirect Dark Matter (DM) signals explaining the recent cosmic-ray anomalies and links cosmic-ray signals of DM to LHC signals of a leptonic Higgs sector.The states of the leptonic Higgs doublet are lighter than about 200 GeV, yielding large 2 tau and 4 tau event rates at the LHC. For the case of annihilations, cosmic photon and neutrino signals are constrained.
We construct extensions of the Standard Model with two Higgs doublets, where there are flavour changing neutral currents both in the quark and leptonic sectors, with their strength fixed by the fermion mixing matrices $V_{CKM}$ and $V_{PMNS}$. These models are an extension to the leptonic sector of the class of models previously considered by Branco, Grimus and Lavoura, for the quark sector. We consider both the cases of Dirac and Majorana neutrinos and identify the minimal discrete symmetry required in order to implement the models in a natural way.
We present a general formalism for analyzing supersymmetric models where the Higgs sector directly couples to the messengers of supersymmetry breaking. Such Higgs-messenger interactions are strongly motivated by the discovery of a Higgs boson near 125 GeV, but they also raise the specter of the mu/B_mu and A/m_H^2 problems. Using our formalism, we identify new avenues to solving these problems through strong dynamics in the messenger sector or hidden sector. Although our formalism is entirely general, we show how it reproduces familiar results in two simplifying limits: one where the hidden se…
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.
The implementation of maximally restrictive texture zeros in the leptonic sector is investigated in the context of two-Higgs-doublet models with Majorana neutrinos. After analyzing all maximally restrictive pairs of leptonic mass matrices with zero entries, we conclude that there are only four texture combinations that are compatible with observations at 3 sigma confidence level and can be implemented through Abelian symmetries in a two-Higgs-doublet model. The compatibility of these textures with current constraints on lepton-flavor-violating processes is also studied. The ultraviolet complet…
In order to generate, in the context of gauge mediation, a Higgs mass around 126 GeV that avoids the little hierarchy problem, we explore a set of models where the messengers are directly coupled to new vector-like fields at the TeV scale in addition to the usual low energy degrees of freedom. We find that in this context, stop masses lighter than 2 TeV and large $A$-terms are generated, thereby improving issues of fine tuning.
The littlest $Higgs$ model with T-parity (called the $LHT$ model) predicts the existence of the T-odd leptons, which can generate contributions to some leptonic processes at the one-loop level. We calculate their contributions to the leptonic $Z$ decay processes $Z\to l\bar{l'}$, $Z\to l\bar{l}$, and $Z\rightarro ν\barν$. We find that the T-odd leptons can give significant contributions to the branching ratios of these decay processes in most of the parameter space. The experimental measurement values might generate constraints on the free parameters of the $LHT$ model.
We consider the version of the Zee model where both Higgs doublets couple to leptons. Within this framework we study charged Higgs decays. We focus on a model with minimal number of parameters consistent with experimental neutrino data. Using constraints from neutrino physics we (i) discuss the reconstruction of the parameter space of the model using the leptonic decay patterns of both of the two charged Higgses, $h_{1,2}^{+}\to \ell_{j}^{+}ν_{i}$, and the decay of the heavier charged Higgs, $h_{2}^{+}\to h^{+}_{1}h^{0}$; (ii) show that the decay rate $Γ(h_{1}^{+}\to μ^{+}ν_{i})$ in general is…
In this work, we study the radiative leptonic decays of $B^-$ and $D^-$ mesons in the standard model and the two-Higgs-doublet-model type II. The results are obtained using the factorization procedure, and the contribution of the order $O(Λ_{\rm QCD}\left/m_Q\right.)$ is included. The numerical results are calculated using the wave-function obtained in relativistic potential model. As a result, the decay mode $B\to γτν_τ$ is found to be sensitive to the effect of the charged Higgs boson. Using the constraint on the free parameters of the two Higgs doublet model given in previous works, we find…
We propose to interpret the 750 GeV diphoton excess in deflected anomaly mediation supersymmetry breaking scenarios, which can naturally predict couplings between a singlet field and vector-like messengers. The CP-even scalar component (S) of the singlet field can serve as the 750 GeV resonance. The messenger scale, which is of order the gravitino scale, can be as light as F_ϕ\sim {\cal O}(10) TeV when the messenger species N_F and the deflection parameter d are moderately large. Such messengers can induce the large loop decay process S \to γγ. Our results show that such a scenario can success…
We address the observed discrepancies in the anomalous magnetic dipole moments (MDM) of the muon and electron by extending the inert two Higgs Doublet Model (2HDM) with SM gauge singlet complex scalar field and singlet Vector-like Lepton (VLL) field. We obtain the allowed parameter space constrained from the Higgs decays to gauge Bosons at LHC, LEP II data and electro-weak precision measurements. The muon and electron MDM's are then explained within a common parameter space for different sets of allowed couplings and masses of the model particles.
The type X (lepton-specific) two-Higgs-doublet model at large $\tanβ$ becomes leptophilic and thus allows a light pseudoscalar $A$ accommodating the observed muon $g-2$ deviation without conflicting with various hadronic constraints. On the other hand, it is strongly constrained by leptonic precision observables such as lepton universality test in the neutral and charged currents. Treating all the lepton universality data in a consistent way, we show how the current data constrain the parameter space of $m_A$ and $\tanβ$ for given degenerate masses of heavy Higgs bosons $H$ and $H^\pm$. While …
We consider the effect of complex Higgs triplets on purely leptonic processes and survey the experimental constraints on the mass and couplings of their single and double charge members. Present day experiments tolerate values of the Yukawa couplings of these scalars at the level of the standard electroweak gauge couplings. We show that the proposed measurement of the ratio $R_{LCD}=σ(ν_μe)/ [σ(\bbν_μe) + σ(ν_e e )]$ would allow to explore a large region of the parameter space inaccessible to the usual ratio $R=σ(ν_μe)/σ(\bbν_μe)$.
A radiative natural SUSY spectrum are proposed in the deflected anomaly mediation scenario with general messenger-matter interactions. Due to the contributions from the new interactions, positive slepton masses as well as a large |A_t| term can naturally be obtained with either sign of deflection parameter and few messenger species (thus avoid the possible Landau pole problem). In this scenario, in contrast to the ordinary (radiative) natural SUSY scenario with under-abundance of dark matter (DM), the DM can be the mixed bino-higgsino and have the right relic density. The 125 GeV Higgs mass ca…
This Letter addresses a provocative question: ``Can the standard electroweak Higgs doublets and their color-triplet partners be the messengers of a low energy gauge-mediated SUSY breaking?" Such a possibility does not seem to be immediately ruled out. If so, it can lead to a very economical scheme with clear-cut predictions quite distinct from those of the conventional gauge-mediated scenario. Namely, we get (i) a single light Higgs below the original SUSY- breaking scale; (ii) tan(beta) = 1; (iii) flavor non-universal, but automatically flavor-conserving soft scalar masses; (iv) a light color…
Higgs boson mass measurement at $\sim 125$ GeV points to a high scale for SUSY specifically the scalar masses. If all the scalars are heavy, supersymmetric contribution to the leptonic $g-2$ moments will be significantly reduced. On the other hand the Brookhaven experiment indicates a 3sigma deviation from the standard model prediction. Here we analyze the leptonic $g-2$ moments in an extended MSSM model with inclusion of a vector like leptonic generation which brings in new sources of CP violation. In this work we consider the contributions to the leptonic $g-2$ moments arising from the excha…
We propose a new framework for understanding the hierarchies of fermion masses and mixings. The masses and mixings of all Standard Model (SM) charged fermions other than top arise from higher dimensional operators involving a messenger scalar S and flavon scalars F_i. The flavons spontaneously break SM flavor symmetries at around the TeV scale. The SM singlet scalar S couples directly to the Higgs H and spontaneously breaks another U(1) at the electroweak scale. At the TeV scale, SM quarks and charged leptons have renormalizable couplings to S, but not to H or F_i. These couplings involve new …
We investigate the effects of messenger-matter mixing on the lightest CP-even Higgs boson mass m_h in gauge-mediated supersymmetry breaking models. It is shown that with such mixings m_h can be raised to about 125 GeV, even when the superparticles have sub-TeV masses, and when the gravitino has a cosmologically preferred sub-keV mass. In minimal gauge mediation without messenger-matter mixing, realizing m_h = 125 GeV would require multi-TeV SUSY spectrum. The increase in $m_h$ due to messenger-matter mixing is maximal in the case of messengers belonging to 10+\bar{10} of SU(5) unification, whi…
We reanalyze the extraction of the heavy Higgs boson signal $H\rightarrow W^+W^-\rightarrow \bar\ellν,\ell\barν$ $(\ell=e\hbox{ or }μ)$ from the Standard Model background at hadron supercolliders, taking into account revised estimates of the top quark background. With new acceptance criteria the detection of the signal remains viable. Requiring a forward jet-tag, a central jet-veto, and a large relative transverse momentum of the two charged leptons yields $S/\sqrt B>6$ for one year of running at the SSC or LHC.
Quantum corrections generate a quadratically divergent mass term for the Higgs boson in the Standard Model. Thus, if the Higgs boson has a mass of order 100 GeV, it implies the presence of a cut-off of the theory around TeV scale, and some particles associated with the new physics may appear around the cut-off scale $Λ$. However, if $Λ$ is several TeV, it may be difficult to find such particles at the LHC. In this paper, we consider a situation in which the new physics provides relatively light particles compared with the scale $Λ$. In such a situation, we show that diphoton event and four lep…
Large long-distance standard model effects in FCNC semileptonic D decays can make observable these processes in future measurements. Eventual disagreements in this sector and/or the observation of lepton family violating (LFV) D decays would require an explanatio beyond the SM framework. In this paper we confront present experimental data on leptonic and semileptonic FCNC and LFV D meson decays with a version of the two-Higgs doublet model that allows these effects to occur at tree- level. The stringent bounds on the parameters of the model are obtained from D^0 --> l^+l'^- and D --> pi l^+l'^…
We derive the leptonic neutral current in the simplest little Higgs model and compute the contribution of the model to the decay width $Z \to e^+e^-$. Using the precision electroweak data we obtain a strong lower bound $f\geq 5.6$ TeV at 95% C.L. on the characteristic energy scale of the model. It results in a lower bound for the new gauge bosons $W^{\prime\pm}$ and $Z^{\prime}$ as being $M_{W^{\prime\pm}}\geq 2.6$ TeV and $M_{Z^{\prime}}\geq 3.1$ TeV, respectively. We also present the allowed values of the $k=f_1/f_2$ which is the parameter relating the two vacuum expectation values of the sc…
We discuss gauge mediation models where the doublet messengers and Higgs doublets are allowed to mix through a "charged" coupling. The charged coupling replaces messenger parity as a means of suppressing flavor changing neutral currents without introducing any unwanted CP violation. As a result of this mixing between the Higgs doublets and the messengers, relatively large A-terms are generated at the messenger scale. These large A-terms produce a distinct weak scale mass spectrum. Particularly, we show that the lightest Higgs boson mass is enhanced and can be as heavy as 125GeV for a gluino ma…
We consider the two-loop corrections to the $HW^+W^-$ vertex at order $αα_s$. We construct a canonical basis for the two-loop integrals using the Baikov representation and the intersection theory. By solving the $ε$-form differential equations, we obtain fully analytic expressions for the master integrals in terms of multiple polylogarithms, which allow fast and accurate numeric evaluation for arbitrary configurations of external momenta. We apply our analytic results to the decay process $H \to ν_e e W$, and study both the integrated and differential decay rates. Our results can also be appli…
We consider the issue of vacuum stability and triviality bound of the singlet extension of the Standard Model (SM) with a singlet fermion dark matter (DM). In this model, the singlet scalar plays the role of a messenger between the SM sector and the dark matter sector. This model has two Higgs-like scalar bosons, and is consistent with all the data on electroweak precision tests, thermal relic density of DM and its direct detection constraints. We show that this model is stable without hitting Landau pole up to Planck scale for 125 GeV Higgs boson. We also perform a comprehensive study of vacu…
CMS has reported indications (2.4σ) of the decay of the Higgs boson into μτ. The simplest explanation for such a decay would be a general Two Higgs Doublet Model (2HDM). In this case, one would expect the heavy neutral Higgs bosons, H and A, to also decay in a similar manner. We study two specific models. The first is the type III 2HDM, and the second is a 2HDM, originally proposed by Branco et al., in which all flavor-changing neutral processes are given by the weak mixing matrix. In the latter model, since mixing between the second and third generations in the lepton sector is large, flavor-…
We consider a renormalizable messenger sector with magic messenger fields instead of usual SU(5) complete multiplets. We derive the soft supersymmetry breaking terms and show that the gaugino sector can be parameterized by only two parameters. These parameters can be chosen appropriately to obtain various patterns of gaugino masses and different ratios among them. The sfermion sector can also be characterized by two independent parameters which can be adjusted to change the relative masses of squarks and sleptons. A judicious choice of parameters also allows us to achieve the lightest Higgs bo…
The leptonic mixing angle $θ_{13}$ is known to be small. If it is indeed tiny, the simplest explanation is that charged leptons mix only in the $μ-τ$ sector and neutrinos only in the 1-2 sector. We show that this pattern may be explained by the discrete symmetry $Z_2 \times Z_2$ of a complete Lagrangian, which has 2 Higgs doublets and 2 Higgs triplets (or 2 heavy right-handed singlet neutrinos). In the case of Higgs triplets, the Majorana neutrino masses are arbitrary, whereas in the case of heavy singlet neutrinos, an inverted hierarchy is predicted. Lepton-Flavor-Violation effects, present o…
In order to raise the Higgs mass up to 125 GeV and relieve the fine-tuning associated with the heavy s-top mass in the minimal supersymmetric standard model (MSSM), we propose a new singlet extension of the MSSM. In this scenario, the additional Higgs mass is radiatively generated also in a hidden sector, and the effect is tansmitted to the Higgs through a messenger field. The Higgs mass can be efficiently increased by the parameters of the superpotential as in the extra matter scenario, but free from the constraints on extra colored matter fields by the LHC experiments. As a result, the tunin…
If tan(beta) is large, down-type quark mass matrices and Yukawa couplings cannot be simultaneously diagonalized, and flavour violating couplings of the neutral Higgs bosons are induced at the 1-loop level. These couplings lead to Higgs-mediated contributions to the decays B_s -> mu+ mu- and B_d -> tau+ tau-, at a level that might be of interest for the current Tevatron run, or possibly, at B-factories. We evaluate the branching ratios for these decays within the framework of minimal gravity-, gauge- and anomaly-mediated SUSY breaking models, and also in SU(5) supergravity models with non-unive…
In this Letter, we study the gamma-ray signatures subsequent to the production of a Higgs boson in space by dark matter annihilations. We investigate the cases where the Higgs boson is produced at rest or slightly boosted and show that such configurations can produce characteristic bumps in the gamma-ray data. These results are relevant in the case of the Standard Model-like Higgs boson provided that the dark matter mass is about 63 GeV, 109 GeV or 126 GeV, but can be generalised to any other Higgs boson masses. Here, we point out that it may be worth looking for a 63 GeV line since it could b…
Searches for a heavy Standard Model Higgs boson focus on the 'gold plated mode' where the Higgs decays to two leptonic Z bosons. This channel provides a clean signature, in spite of the small leptonic branching ratios. We show that using fat jets the semi-leptonic ZZ mode significantly increases the number of signal events with a similar statistical significance as the leptonic mode.
We show that the messenger-matter couplings of Flavored Gauge Mediation Models can generate substantial stop mixing, leading to Higgs masses around 126 GeV with colored superpartners below 2 TeV and even a TeV. These results are largely independent of the messenger scale. We study the spectra of a few examples with a single messenger pair coupling dominantly to the top, for different messenger scales. Flavor constraints in these models are obeyed by virtue of supersymmetric alignment: the same flavor symmetry that explains fermion masses dictates the structure of the matter-messenger couplings…
We study the Higgs boson decay to W+W-, where one boson decays to leptons, and the other decays to c+jet at Tevatron. Given the current charm tagging acceptances, this channel can help improve and confirm the current combined Tevatron exclusion limit on a standard model-like Higgs boson. If charm acceptance can be improved to at least 24%, this channel could provide the second tightest limits on a Higgs boson mass between 140-190 GeV from a single channel measurement.
We show that direct CP violation in semi-leptonic and leptonic decays can occur in multi-Higgs doublet extensions of the electroweak standard model with flavor changing neutral currents. For pion and lepton decays these $CP$ violating effects cannot be constrained directly by experimental data since up to now the branching ratio of the decays $π^-$ and $μ^-$ have not been measured in laboratory.
We compute the hadronic production of top-antitop pairs in association with a Higgs boson at next-to-leading-order QCD, including the decay of the top and antitop quark into bottom quarks and leptons. Our computation is based on full leading and next-to-leading-order matrix elements for $e^+ ν_e μ^-\barν_μb \bar{b} H(j)$ and includes all non-resonant contributions, off-shell effects and interferences. Numerical results for the integrated cross section and several differential distributions are given for the LHC operating at 13 TeV using a fixed and a dynamical factorization and renormalization…
Possibility of observing associated production of charged Higgs and W boson in the framework of MSSM at LHC is studied. Both leptonic and hadronic decays of W boson are studied while the charged Higgs boson is considered to decay to a $τ$ lepton and a neutrino. Therefore two search categories are defined based on the leptonic and hadronic final states, i.e. $\ell τ+E^{miss}_{T}$ and $jj τ+E^{miss}_{T}$ where $\ell=e$ or $μ$ and $j$ is a light jet from $W$ decay. The discovery chance of the two categories is evaluated at an integrated luminosity of 300 \invfb at LHC. It is shown that both lepto…
Recent signs of a Standard Model-like Higgs at 125 GeV point towards large A-terms in the MSSM. This presents special challenges for gauge mediation, which by itself predicts vanishing A-terms at the messenger scale. In this paper, we review the general problems that arise when extending gauge mediation to achieve large A-terms, and the mechanisms that exist to overcome them. Using these mechanisms, we construct weakly-coupled models of low-scale gauge mediation with extended Higgs-messenger couplings that generate large A-terms at the messenger scale and viable mu/B_mu-terms. Our models are s…
We present a simple model that achieves $m_h\approx 126$ GeV in the MSSM with large $A$-terms and TeV-scale stops through a combination of gauge mediation and Higgs-messenger interactions. The $μ$/$B_μ$ and $A$/$m_H^2$ problems are both solved by a common mechanism -- partial sequestering from strong hidden sector dynamics. Using the framework of General Messenger Higgs Mediation, we explicitly calculate the soft masses in terms of the vacuum expectation values, operator dimensions and OPE coefficients of the strongly-coupled hidden sector. Along the way, we also present a general analysis of …
We study di-boson production via both neutral and charged current at the Large Hadron Collider, i.e. subprocesses $q\bar q\to e^+ν_e μ^-\barν_μ$ + ${\rm{c.c.}}$ and $q\bar q'\to l^+ν_l l^{'+}l^{'-}$ + ${\rm{c.c.}}$, respectively, where $q,q'$ are quarks and $l,l'=e,μ$, in all possible combinations, in the context of the 4-Dimensional Composite Higgs Model. These modes enable the production in the intermediate steps of several additional -- with respect to the Standard Model -- neutral and charged gauge bosons belonging to the spectrum of this scenario, all of which in resonant topologies. We n…
We address the mu problem of gauge mediation by considering a singlet chiral superfield coupled to the Higgs and messenger fields. We compute the soft terms generated below the messenger scale and study the phenomenological consequences of the model. The experimental bound on the Higgs mass provides a severe constraint that identifies three special regions of parameters where the mass spectrum and the collider signatures can be distinct from ordinary gauge mediation.
Recent observation shows that the Higgs mass is at around 125 GeV while the prediction of the minimal supersymmetric standard model is below 120 GeV for stop mass lighter than 2 TeV unless the top squark has a maximal mixing. We consider the right-handed neutrino supermultiplets as messengers in addition to the usual gauge mediation to obtain sizeable tri-linear soft parameters $A_t$ needed for the maximal stop mixing. Neutrino messengers can explain the observed Higgs mass for stop mass around 1 TeV. Neutrino assistance can also generate charged lepton flavor violation including $μ\to e γ$ as…
The Little Higgs model with T-parity (LHT) belongs to the non-minimal flavour violating model. This model has new sources of flavour and CP violation both in quark and leptonic sectors. These new sources of flavour violation originates by the interaction of Standard Model (SM) fermions with heavy gauge bosons and heavy (or mirror) fermions. In this work we will present the impact of the new flavour structure of T-parity models on flavour violations in leptonic sector.
The new results on the muon anomalous magnetic moment (AMM) published by Fermilab in 2021, did not lead to a reduction of its long-pending deviation from the Standard Model (SM) value by more than 4$σ$. The explanation of this discrepancy by adding new particles to the theory puts many new physics models under tension when combined with the null results of the LHC direct searches for new particles. In this paper, we investigate the CP-violating Next-to-Minimal Supersymmetric extension of the SM (NMSSM) with and without an inverse seesaw mechanism. We compute the one-loop supersymmetric contrib…
Recent data from the ATLAS and CMS detectors at the Large Hadron Collider at CERN give a hint of possible violation of flavor in the leptonic decays of the Higgs boson. In this work we analyze the flavor violating leptonic decays $H^0_1\to l_i \bar l_j$ ($i\neq j$) within the framework of an MSSM extension with a vectorlike leptonic generation. Specifically we focus on the decay mode $H^0_1\to μτ$. The analysis is done including tree and loop contributions involving exchange of $W, Z$, charge and neutral higgs and leptons and mirror leptons, charginos and neutralinos and sleptons and mirror sl…
We investigate the semileptonic and leptonic B decays, B to D^{(*)} tau nu and B to tau nu in our multi-Higgs-doublet models, while keeping in mind the enhancement of the top forward-backward (FB) asymmetry (A^t_{FB}) at the Tevatron. In these models, the extra (pseudo)scalar bosons contribute to A^t_{FB} with large flavor-changing Yukawa couplings involving the top quark, but the contribution of the charged Higgs boson to A^t_{FB} is negligible. However, it may significantly affect B decays: especially, B to D^{(*)} tau nu and B to tau nu. We investigate the constraints on the B decays, based…
We demonstrate the potential of fully leptonic cascade decays of a heavy neutral Higgs boson through vectorlike leptons as a simultaneous probe for extended Higgs sectors and extra matter particles at the LHC. The processes we explore are unique in that their event topologies lead to di-boson-like leptonic final states with a lepton pair which does not reconstruct the mass of a gauge boson. By recasting existing $2\ell + E_T^{\rm miss}$ and $3/4\ell$ searches channels using run2 data from the LHC we obtain $\textit{model independent}$ bounds on the masses of heavy scalars and vectorlike lepton…
