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H. T. Hung

Publications and source records attributed to H. T. Hung.

At least 19 recordsLinked to original sources
arXiv2026

Heavy neutral bosons and dark matter in the 3-3-1 model with axionlike particle

We consider heavy neutral bosons in the 3-3-1 model with axionlike particles (331ALP), including the Higgs boson and the $Z^\prime$ boson which are outside the standard model (SM). Based on gluon-gluon fusion at the LHC, we investigate the signals of cross-sections in the parameter space region satisfying the current experimental limits of lepton flavor violating decay, including processes involving both charged leptons and Higgs boson, and provide predictions of $m_{h_2}\geq 630 ~\mathrm{GeV}$. A new gauge boson, labeled as $Z^{\prime}$, has its mass excluded in the smaller domain $5.1 ~\mathrm{TeV}$ based on investigating the cross-section of the processes that $Z^{\prime}$ mediates combined with experimental limits of the search for high-mass dilepton resonances at ATLAS and CMS. We consider the stability of odd-$Z_2$ particles, with $Z_2$ is assumed a residual symmetry after spontaneous symmetry breaking stages, to point out dark matter candidates in the model. Investigating the relic density of dark matter within experimentally permissible limits, we established a relationship between the mass of dark matter and the breaking scale of axion.

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arXiv2026

Probing muon anomaly and lepton flavor violation with scalar leptoquarks in the 331LHN model

We extend the $SU(3)_C \times SU(3)_L \times U(1)_X$ model with neutral leptons (331LHN) by introducing scalar leptoquarks. We determine the particle content of the leptoquark multiplets and their Yukawa interactions with fermions. We find that a singlet leptoquark can fully account for the $4.2σ$ discrepancy in the muon anomalous magnetic moment $Δa_μ^{2021}$. The corresponding leptoquark mass is constrained to be $m_S \gtrsim 1.8$~TeV, consistent with current LHC bounds. We further consider the updated $Δa_μ^{2025}$ based on recent lattice QCD results, which strengthen the lower bound to $m_S \gtrsim 6$~TeV. Combining $Δa_μ$ with low-energy leptonic observables, including charged lepton flavor violation and the $μ$--$e$ conversion rate, we constrain the viable parameter space. The allowed leptoquark Yukawa couplings exhibit a normal hierarchical pattern under all constraints. We also investigate the collider phenomenology of the singlet leptoquark, showing that its QCD-driven pair production leads to suppressed signal rates at the LHC for multi-TeV masses, while future hadron colliders can significantly extend the discovery reach.

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arXiv2026

Extended IDM theory with low scale seesaw mechanisms

We have developed an extension of the inert doublet model in which the CP-phases in the weak sector are generated from one-loop level corrections mediated by dark fields, while the strong-CP phase arises at three-loop. In this framework, the tiny masses of the active neutrinos are produced through a radiative inverse seesaw mechanism at a two-loop level, the masses of the first and second families of SM-charged fermions arise from a one-loop level radiative seesaw mechanism, and the third generation of SM charged fermion masses are generated at tree level. We have demonstrated that the proposed model successfully accounts for SM fermion masses and mixings. The radiative nature of the seesaw mechanisms is attributed to preserved discrete symmetries, which are required for ensuring the stability of fermionic and scalar dark matter candidates. The preserved discrete symmetries also allow for multi-component dark matter, whose annihilation processes permits to successfully reproduce the measured amount of dark matter relic abundance for an appropriate region of parameter space, which has shown to be compatible with current dark matter direct detection limits. Besides that, we explore the model's ability to explain the $95$ GeV diphoton excess observed by the CMS collaboration, showing that it readily accommodates this anomaly. We have shown that charged lepton flavor violating decays acquire rates within the current experimental sensitivity.

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arXiv2025

Lepton Flavor Physics in the flipped 3-3-1-1 Model: Non-Universality and Violation

We investigate the flavor violation (FV) of Z decays to leptons at tree level and flavor conserving Z decays to leptons in the frame work of the flipped $ SU(3)_C\otimes SU(3)_L \otimes U(1)_X\otimes U(1)_N$,(F3311) model. In addition, we analyze the processes $l_i\rightarrow l_j γ$ and the leptonic three-body decay. Using the experimental bounds on these decays we set the constraint on $\sin ϕ$ which represents the mixing between Z-Z' boson. The most stringent limits arises from $μ\rightarrow e γ$ decay where $\sin ϕ\sim \mathcal{ O}(10^{-3})$. The leptonic three-body decay set lower bound on the mass of the new neural gauge boson $m_{Z'} \geq 3.2TeV$. Using the LUX-ZEPLIN (LZ) experiment data we set bounds to the mass of the dark matter candidates. Subsequently, we investigate the lepton non-universality in B decays within the $F3311$ model by calculating the generic one-loop contribution to the process $u_i\rightarrow d_j e_b \barν_a$ in the unitary gauge as well as numerical evaluating the branching ratio $R_D, R_{D^{(*)}},R(X_c)$. We demonstrate that the $F3311$ model can address the $3.3 σ$ discrepancies between Standard Model and experimental data. To reaffirm our results, we also analyze the $d \to u$ transitions and $s\to u$ transitions. These two transitions also give consistent result with experiment data. Combine all experiment dat a we obtain the operating region for the mass of the model specifically $m_E \in [6.5, 9 ]TeV$, $m_Q \in [6,11]TeV$ and the dark matter candidate $m_ξ\in [1.5,2 ]TeV$.

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arXiv2025

On axion properties in the 3-3-1 model with $U(1)_{B-L}$ and Peccei-Quinn symmetries

The Peccei-Quinn ($PQ$) mechanism is applied to the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X}$ model with $U(1)_{B-L}$ symmetry. The structures in the $PQ$ charges of all fermions and scalar fields in the model are investigated by applying the invariant condition under the symmetry group transformations on all Yukawa interaction terms. All defined $PQ$ charges depend just on the $PQ$ charge of the complex singlet scalar field which causes the $U(1)_{PQ}$ spontaneous symmetry breaking in the model. The mixing and mass hierarchy in the scalar sector of the model are studied in detail. The constraints on the $PQ$ charges and imaginary parts of scalars are derived. It is shown that only neutral scalar fields carry $PQ$ charges while charged ones do not. As the result, the physical state of axion which obeys the invariance under $\mathrm{SU(3)_L \otimes U(1)_X}$ and $PQ$ transformations, is a linear combination of all imaginary parts associated with the $X$ charges of scalar triplets. The anomaly axion-fermion interactions are presented. Explicit expressions for axion and light Standard Model (SM) like Higgs boson are shown. Mass of the axion and its coupling to photon are derived. The decays of the SM-like Higgs boson into a pair of either charged leptons or bottom quarks are presented and constrained. The triple-coupling axion-photon-photon arisen from kinetic terms of scalar fields is derived. Hence, the decay of axion into a pair of photons consists of two parts: the first is related to the anomaly coupling and the second is come from kinetic terms of scalar fields. The result shows that the new contribution can be helpful for searching axion with mass at hundred keV.

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arXiv2023

Investigation of CP-even Higgs bosons decays $H \rightarrow μτ$ within constraints of $l_a \rightarrow l_b γ$ in a 3-3-1 model with inverse seesaw neutrinos

In a 3-3-1 model with inverse seesaw neutrinos, we use a simple form of Higgs potential to give four CP-even Higgs bosons ($H \equiv h^0_1,h^0_2,h^0_3,h^0_4$). We investigate $H \rightarrow μτ$ decays in the parameter space regions satisfying the experimental limits of $l_a \rightarrow l_b γ$ with running parameters being the mass of the charged Higgs boson ($m_{H_1^\pm}$) and the mixing matrix of the heavy neutrinos ($M_R$). We show that there exist regions of parameter space where all partial widths $Γ(H \rightarrow μτ)$ are less than the current experimental limit ($4.1 \times 10^{-6} GeV$). Analyzing the contributing components to $Γ(H \rightarrow μτ)$, we also compare the mass of the SM-like Higgs boson with the corresponding ones of the other CP-even Higgs bosons in this model.

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arXiv2023

Decays of CP-even Higgs bosons $H \rightarrow l_il_j$ in a 3-3-1 model with neutral leptons

The 3-3-1 model with neutral leptons contains four CP-even Higgs bosons when some constraints are imposed on the Higgs potential. Two Higgs bosons of this type are identified with the corresponding ones in the Two-Higgs-Doublet model (2HDM), an other being more massive does not couple with similar particles contained in the Standard Model (SM). The remaining particle is assumed to have no lepton-flavor-violating couplings. The contributions at one-loop order to $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$$(H \equiv h^0_1,h^0_2,h^0_3)$ come mainly from neutral leptons leading them to depend very strongly on mass of charged Higgs boson, masses and the mixing matrix ($V^L_{ab}$) of the neutral leptons. The numerical investigated results of $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$ in the spatial regions satisfying the experimental limit of lepton-flavor-violating decays of charged leptons (cLFV) indicate that the signal of SM-like Higgs boson ($\mathrmΓ(h^0_1\rightarrow l_il_j)$) approaches the upper bound of the experimental limit and $\mathrmΓ(\mathrm{H}\rightarrow l_il_j)$ can take large values in the case of $V^L_{ab} = U^L_{ab}(π/4,π/4,-π/4)$ and smaller in the case of $V^L_{ab} = U^L_{ab}(π/4,0,0)$. Further, some distinct properties of $\mathrmΓ(h^0_2\rightarrow l_il_j)$ and $\mathrmΓ(h^0_3\rightarrow l_il_j)$ are also discussed.

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arXiv2022

An explanation of experimental data of $(g-2)_{e,μ}$ in 3-3-1 models with inverse seesaw neutrinos

We show that the anomalous magnetic moment experimental data of muon and electron $(g-2)_{μ,e}$ can be explained simultaneously in simple extensions of the 3-3-1 models consisting of new heavy neutrinos and a singly charged Higgs boson. The heavy neutrinos generate active neutrino masses and mixing through the general seesaw mechanism. They also have non-zero Yukawa couplings with singly charged Higgs bosons and right-handed charged leptons, which result in large one-loop contributions known as \emph{chirally-enhanced} ones. Numerical investigation confirms a conclusion indicated previously that these contributions are the key point to explain the large $(g-2)_{μ,e}$ data, provided that the inverse seesaw mechanism is necessary to allow both conditions that heavy neutrino masses are above few hundred GeV and non-unitary part of the active neutrino mixing matrix must be large enough.

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arXiv2022

Large signal of $h \rightarrow μτ$ within the constraints of $e_i \rightarrow e_jγ$ decays in the 3-3-1 model with neutral leptons

In the framework of the 3-3-1 model with neutral leptons, we have investigated the lepton-flavor-violating sources based on the Higgs mass spectrum which has two neutral Higgses identitied with corresponding ones in the Two-Higgs-Doublet model (THDM). On the $13~\mathrm{TeV}$ scale of the LHC, we point out the parameter space regions where the experimental limits of $e_i \rightarrow e_jγ$ decays are satisfied. These regions depend heavily on the mixing of exotic leptons but are predicted to have large $h^0_1\rightarrow μτ$ signals. We also show that $\mathrm{Br}(h^0_1\rightarrow μτ)$ can reach a value of $10^{-4}$.

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arXiv2021

Contribution of heavy neutrinos to decay of standard-model-like Higgs boson $h\rightarrow μτ$ in a 3-3-1 model with additional gauge singlets

In the framework of the improved version of the 3-3-1 models with right-handed neutrinos, which is added to the Majorana neutrinos as new gauge singlets, the recent experimental neutrino oscillation data is completely explained through the inverse seesaw mechanism. We show that the major contributions to $Br(μ\rightarrow eγ)$ are derived from corrections at 1-loop order of heavy neutrinos and bosons. But, these contributions are sometimes mutually destructive, creating regions of parametric spaces where the experimental limits of $Br(μ\rightarrow eγ)$ are satisfied. In these regions, we find that $Br(τ\rightarrow μγ)$ can achieve values of $10 ^{- 10}$ and $Br(τ\rightarrow eγ)$ may even reach values of $10 ^{- 9}$ very close to the upper bound of the current experimental limits. Those are ideal areas to study lepton-flavor-violating decays of the standard- model- like Higgs boson ($h_1^0$). We also pointed out that the contributions of heavy neutrinos play an important role to change $Br(h_1^0\rightarrow μτ)$, this is presented through different forms of mass mixing matrices ($M_R$) of heavy neutrinos. When $M_R \sim diag(1,1,1)$, $Br(h_1^0\rightarrow μτ)$ can get a greater value than the cases $M_R \sim diag(1,2,3)$ and $M_R \sim diag(3,2,1)$ and the largest that $Br(h_1^0\rightarrow μτ)$ can reach is very close $10 ^{-3}$.

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arXiv2020

Lepton flavor violating decays of the SM-like Higgs boson $h\rightarrow e_ie_j$, and $e_i \rightarrow e_j\, γ$ in a flipped 3-3-1 model

In the framework of the flipped 3-3-1 model introduced recently [1], the lepton-flavor-violating (LFV) decay $μ\rightarrow 3e$ was predicted to have a large branching ratio (Br) close to the recent experimental limit. We will show that the Br of LFV decays of the standard-model-like (SM-like) Higgs boson decays (LFVHD) Br$(h\rightarrow e_ae_b)$ may also be large. Namely, the Br$(h\rightarrow μτ,eτ)$ can reach values of $\mathcal{O}(10^{-4})-\mathcal{O}(10^{-5})$, which will reach the upcoming experimental sensitivities. On the other hand, for LFV decays of charged leptons (cLFV) $(e_b\rightarrow e_aγ)$, the branching ratios are well below experimental bounds.

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arXiv2019

Neutral Higgs decays $H \rightarrow Z γ,γγ$ in 3-3-1 models

The significance of new physics appearing in the loop-induced decays of neutral Higgs bosons into pairs of dibosons $γγ$ and $Zγ$ will be discussed in the framework of the 3-3-1 models based on a recent work~\cite{Okada:2016whh}, where the Higgs sector becomes effectively the same as that in the two Higgs doublet models (2HDM) after the first symmetry breaking from $SU(3)_L$ scale into the electroweak scale. For large $SU(3)_L$ scale $v_3\simeq10$ TeV, dominant one-loop contributions to the two decay amplitudes arise from only the single charged Higgs boson predicted by the 2HDM, leading to that experimental constraint on the signal strength $μ^{331}_{γγ}$ of the Standard Model-like Higgs boson decay $h\rightarrow γγ$ will result in a strict upper bound on the signal strength $μ^{331}_{Zγ}$ of the decay $h\rightarrow\, Zγ$. For a particular model with lower $v_3$ around 3 TeV, contributions from heavy charged gauge and Higgs bosons may have the same order, therefore may give strong destructive or constructive correlations. As a by-product, a deviation from the SM prediction $|μ^{331}_{γγ}-1| \le 0.04$ still allows $|μ^{331}_{Zγ}-1|$ to reach values near 0.1. We also show that there exists an $CP$-even neutral Higgs boson $h^0_3$ predicted by the 3-3-1 models, but beyond the 2HDM, has an interesting property that the branching ratio Br$(h^0_3\rightarrow γγ)$ is very sensitive to the parameter $β$ used to distinguish different 3-3-1 models.

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arXiv2017

Lepton flavor violating Higgs boson decays in seesaw models: new discussions

The lepton flavor violating decay of the Standard Model-like Higgs boson (LFVHD), h->μτ, is discussed in seesaw models at the one-loop level. Based on particular analytic expressions of Passarino-Veltman functions, the two unitary and 't Hooft Feynman gauges are used to compute the branching ratio of LFVHD and compare with results reported recently. In the minimal seesaw (MSS) model, the branching ratio was investigated in the whole valid range 10^{-9}-10^{15} GeV of new neutrino mass scale m_{n_6}. Using the Casas-Ibarra parameterization, this branching ratio enhances with large and increasing m_{n_6}. But the maximal value can reach only order of 10^{-11}. Interesting relations of LFVHD predicted by the MSS and inverse seesaw (ISS) model are discussed. The ratio between two LFVHD branching ratios predicted by the ISS and MSS is simply m^2_{n_6}μ^{-2}_X, where μ_X is the small neutrino mass scale in the ISS. The consistence between different calculations is shown precisely from analytical approach.

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arXiv2016

One loop contributions to neutral Higgs decay h-->mu tau

In calculating one-loop contributions to amplitudes of the lepton-flavor violating decays of the neutral Higgses (LFVHD) to different flavor charged leptons, the analytic expressions can be written in term of Passarino-Veltman functions. Then, they can be computed numerically by Looptools [1]. Another approach is using suitable analytic expressions established for just this particular case. We compare numerical results obtained from Looptools and those computed by different expressions that have been applied recently. Then we derive the preferable ones that are applicable for the large ranges of free parameters introduced in the models beyond the Standard Model (SM). For illustration, the LFVHD in a simple model, which has been discussed recently, will be investigated more precisely.

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arXiv2015

Signal of doubly charged Higgs at $e^+e^-$ colliders

Masses and signals of the production of Doubly charged Higgses(DCH) in the framework of the supersymmetric reduced minimal 3-3-1 model(SUSYRM331) are investigated. In the DCH sector, weprove that there always exists a region of the parameter space where the mass of the lightest DCH is in order of $\mathcal{O}(100)$ GeV even when all other new particles are very heavy.The lightest DCH mainly decays to two same-sign leptons while the dominated decay channels of the heavy DCHs are those decay to heavy particles. We analyze each production cross section for $e^+e^- \rightarrow H^{++} H^{--}$ as a function of a few kinematic variables, which are useful to discuss the creation of the DCHs in the $e^+e^-$ colliders as a signal of new physics beyond the Standard Model. The numerical study shows that the cross sections for creating the lightest DCH can reach values of few pbs. The two other DCHs are too heavy, beyond the observable range of experiments. The lightest DCH may be detected by the International Linear Collider (ILC) or the Compact LInear Collider (CLIC) by searching its decay to a same-sign charged lepton pair.

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arXiv2013

3-3-1-1 model for dark matter

We show that the SU(3)_C X SU(3)_L X U(1)_X (3-3-1) model of strong and electroweak interactions can naturally accommodate an extra U(1)_N symmetry behaving as a gauge symmetry. Resulting theory based on SU(3)_C X SU(3)_L X U(1)_X X U(1)_N (3-3-1-1) gauge symmetry realizes B-L=-(2/\sqrt{3})T_8+N as a charge of SU(3)_L X U(1)_N. Consequently, a residual symmetry, W-parity, resulting from broken B-L in similarity to R-parity in supersymmetry is always conserved and may be unbroken. There is a specific fermion content recently studied in which all new particles that have wrong lepton-numbers are odd under W-parity, while the standard model particles are even. Therefore, the lightest wrong-lepton particle (LWP) responsible for dark matter is naturally stabilized. We explicitly show that the non-Hermitian neutral gauge boson (X^0) as LWP cannot be a dark matter. However, the LWP as a new neutral fermion (N_R) can be dark matter if its mass is in range 1.9 TeV \leq m_{N_R} \leq 2.5 TeV, provided that the new neutral gauge boson (Z') mass satisfies 2.2 TeV \leq m_Z' \leq 2.5 TeV. Moreover, the scalar dark matter candidate (H'\simeq η_3) which has traditionally been studied is only stabilized by W-parity. All the unwanted interactions and vacuums as often encountered in the 3-3-1 model are naturally suppressed. And, the standing issues on tree-level flavor changing neutral currents and CPT violation also disappear.

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arXiv2012

Question of Peccei-Quinn symmetry and quark masses in the economical 3-3-1 model

We show that there is an infinite number of U(1) symmetries like Peccei-Quinn symmetry in the 3-3-1 model with minimal scalar sector---two scalar triplets. Moreover, all of them are completely broken due to the model's scalars by themselves (notice that these scalars as known have been often used to break the gauge symmetry and generating the masses for the model's particles). There is no any residual Peccei-Quinn symmetry. Because of the minimal scalar content there are some quarks that are massless at tree-level, but they can get consistent mass contributions at one-loop due to this fact. Interestingly, axions as associated with the mentioned U(1)s breaking (including Majoron due to lepton-charge breaking) are all gauged away because they are also the Goldstone bosons responsible for the gauge symmetry breaking as usual.

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