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T. T. Hong

Publications and source records attributed to T. T. Hong.

15 recordsLinked to original sources

LFV decays in a 3-3-1 model with singlet leptoquarks

Motivated by a recent study of the 3-3-1 model supplemented with a singlet scalar leptoquark, which successfully explains the muon anomalous magnetic moment and the decay $\mu\to e\gamma$ within current experimental constraints, we extend the phenomenological analysis of this framework to include the lepton-flavor-violating decays of the Standard Model-like Higgs and the $Z$ boson. An interesting feature is that the branching ratios of these decays exhibit a nearly linear correlation with the corresponding charged lepton flavor-violating radiative decays, namely $\mathrm{Br}(h,Z\to e_b^\pm e_a^\mp)\propto\mathrm{Br}(e_b\to e_a\gamma)$. Furthermore, the model exhibits a complementary interplay between the charged-lepton anomalous magnetic moments: parameter regions with $|\Delta a_{\mu}|\geq10^{-11}$ favor $\mathrm{Br}(h,Z\to\tau^\pm\mu^\mp)$ reaching their current experimental upper limits while keeping $|\Delta a_e|$ negligible, whereas regions with $10^{-14}\leq|\Delta a_e|\leq 8\times10^{-13}$ instead allow $\mathrm{Br}(h,Z\to\tau^\pm e^\mp)$ to approach the present experimental sensitivities but simultaneously suppress $|\Delta a_\mu|$ to the level of $\mathcal{O}(10^{-16})$.

hep-ph

LFV decays in a 3-4-1 model with minimal inverse seesaw neutrinos

We investigate an extended 3-4-1 model consisting of a new singly charged Higgs boson, implementing the minimal inverse seesaw mechanism to account for the current $(g-2)_{e,\mu}$ constraints as well as the lepton-flavor-violating decay rates of charged leptons, the Standard Model-like Higgs boson, and the $Z$ boson, all consistent with current experimental data. Unlike the previously studied 3-4-1 realization, the model considered here predicts strong correlations among these observables that can be tested in future experiments. In particular, the current upper bound on Br$(\tau \to \mu \gamma)$ imposes a stringent constraint compatible with the $1\sigma$ experimental range of $(g-2)_{\mu}$, corresponding to an allowed deviation of order $10^{-9}$ from the SM prediction. The forthcoming experimental sensitivity to Br$(\tau \to \mu\gamma)$ will reduce this deviation to $5\times 10^{-10}$.

hep-ph

$(g-2)_{e,μ}$ and Lepton flavor violating decays in a left-right model

General expressions for one-loop contributions associated with lepton-flavor violating decays of the standard model-like Higgs boson $h\to e_b^\pm e_a^\mp$ and gauge boson $Z\to e^\pm_b e_a^\mp$ are introduced in the unitary gauge. The results are used to discuss these decays as new physics signals in a minimal left-right symmetric model containing only one bidoublet Higgs and a $SU(2)_R$ Higgs doublet accommodating data of neutrino oscillations and $(g-2)_μ$. The numerical investigation indicates that some of these decay rates can reach near future experimental sensitivities.

hep-ph

Decays $Z\to e_ae_b$ in a 3-3-1 model with neutral leptons

We investigate the 3-3-1 model with neutral leptons (called the 331$NL$ for short) and by that, we will point out that this model can simultaneously explain the lepton flavor violating (LFV) decays of the $Z$ boson $Z \to e_a e_b$, Standard model-like Higgs boson decay $h\to e_be_a$, and the charged leptons $e_b\to e_a γ$ consistent with the recent experimental data. In addition, the numerical results show strict relations among these decay rates of $Z$ and $h$ which are predicted by this model. As a result, the decay channels can be determined theoretically if one of them is detected by experiments.

hep-ph

$(g-2)_{e,μ}$ anomalies and decays $h, Z\to e_b e_a $ in 3-3-1 models with inverse seesaw neutrinos

The lepton flavor violating (LFV) decays $h, Z\to e_b e_a $, and $e_b\to e_a γ$ are discussed in a class of general 3-3-1 models adding heavy neutral leptons and singly charged Higgs bosons to accommodate experimental data of neutrino oscillation and $(g-2)_{e_a}$ anomalies of charged leptons through the inverse seesaw mechanism. We show that the models with the minimal number of inverse seesaw neutrinos cannot reach the $1σ$ range of $(g-2)_μ$ data due to the experimental upper bounds on decay rates of $(τ\to μγ)$ and $(μ\to e γ)$. Features of LFV decays are presented in detail, focusing on the regions of parameter space satisfying the $1σ$ ranges of $(g-2)_{e,μ}$ data.

hep-ph

$(g-2)_{e,μ}$ anomalies and decays $h\to e_a e_b$, $Z\to e_ae_b$, and $e_b\to e_a γ$ in a two Higgs doublet model with inverse seesaw neutrinos

The lepton flavor violating decays $h\to e_b^\pm e_a^\mp $, $Z\to e_b^\pm e_a^\mp$, and $e_b\to e_a γ$ will be discussed in the framework of the Two Higgs doublet model with presence of new inverse seesaw neutrinos and a singly charged Higgs boson that accommodate both $1σ$ experimental data of $(g-2)$ anomalies of the muon and electron. Numerical results indicate that there exist regions of the parameter space supporting all experimental data of $(g-2)_{e,μ}$ as well as the promising LFV signals corresponding to the future experimental sensitivities.

hep-ph

Decays of Standard Model like Higgs boson $h \rightarrow\gamma\gamma, Z \gamma$ in a minimal left-right symmetric model

Two decay channels $h\rightarrow \gamma \gamma, Z\gamma$ of the Standard Model-like Higgs in a left-right symmetry model are investigated under recent experimental data. We will show there exist one-loop contributions that affect the $h\rightarrow Z\gamma$ amplitude, but not the $h\rightarrow \gamma\gamma$ amplitude. From numerical investigations, we show that the signal strength $\mu_{Z \gamma}$ of the decay $h\rightarrow Z\gamma$ is still constrained strictly by that of $h\rightarrow \gamma\gamma$, namely $|\Delta \mu_{\gamma \gamma}|<38\%$ results in max $|\Delta \mu_{Z \gamma}|<46\%$. On the other hand, the future experimental sensitivity $|\Delta \mu_{\gamma \gamma}|=4\%$ still allows $|\Delta \mu_{Z \gamma}|$ reaches to values larger than the expected sensitivity $|\Delta \mu_{Z \gamma}|=23\%$.

hep-ph

$(g-2)_{e,μ}$ and decays $e_b\to e_aγ$ in a $ \mbox{SU}(4)_L \otimes \mbox{U}(1)_X$ model with inverse seesaw neutrinos

We will show that the 3-4-1 model with heavy right-handed neutrinos can explain the recent experimental data of $(g-2)_{e, μ}$ anomalies of charged leptons and neutrino oscillations through the inverse seesaw mechanism. In addition, the model can predict large lepton flavor violating decay rates $μ\to eγ$ and $τ\to μγ, eγ$ up to the recent experimental sensitivities.

hep-ph

Heavy singly charged Higgs bosons and inverse seesaw neutrinos as origins of large $(g-2)_{e,μ}$ in two higgs doublet models

We show that simple extensions of two Higgs doublet models consisting of new heavy neutrinos and a singly charged Higgs boson singlet can successfully explain the experimental data on muon and electron anomalous magnetic moments thanks to large chirally-enhanced one-loop level contributions. These contributions arise from the large couplings of inverse seesaw neutrinos with singly charged Higgs bosons and right-handed charged leptons. The regions of parameter space satisfying the experimental data on $(g-2)_{e,μ}$ anomalies allow heavy singly charged Higgs boson masses above the TeV scale, provided that heavy neutrino masses are above few hundred GeV, the non-unitary part of the active neutrino mixing matrix must be large enough, two singly charged Higgs bosons are non degenerate, and the mixing between singly charged Higgs bosons must be non-zero.

hep-ph

Decays $h\to e_ae_b$, $e_b\to e_aγ$, and $(g-2)_{e,μ}$ in a 3-3-1 model with inverse seesaw neutrinos

We will show that the 3-3-1 model with new heavy right handed neutrinos as $SU(3)_L$ singlets can explain simultaneously the lepton flavor violating decays of the SM-like Higgs boson, charged lepton flavor violating decays $e_b\rightarrow e_aγ$, and the electron $(g-2)_e$ anomalies under recent experimental data. The discrepancy of $(g-2)_μ$ predicted by the model under consideration and that of the standard model can reach $10^{-9}$. The decay rates of the standard model-like Higgs boson $h\to τe, τμ$ can reach the values of $\mathcal{O}(10^{-4})$.

hep-ph

Low energy phenomena of the lepton sector in an $A_4$ symmetry model with heavy inverse seesaw neutrinos

An extension of the two Higgs doublet model including inverse seesaw neutrinos and neutral Higgs bosons was constructed based on the $A_4$ symmetry in order to explain the recent neutrino oscillation data. This model can distinguish two well-known normal and inverted order schemes of neutrino data once both the effective masses $m_β$ in tritium beta decays and $\langle m\rangle$ in the neutrinoless double beta decay are observed. The lepton flavor violating decays of the charged leptons $e_b\rightarrow e_aγ$, $μ\rightarrow3e$, the Standard model-like Higgs boson decays $h\rightarrow e_be_a$, and the $μ$-e conversions in some nuclei are generated from loop corrections. The experimental data of the branching ratio Br$(μ\rightarrow eγ, 3e)$ predict that the upper bounds of Br$(τ\rightarrow μγ,eγ)$ and Br$(h\rightarrow e_{a}e_b)$ are much smaller than the planned experimental sensitivities. In contrast, the $μ$-e conversions are the promising signals for experiments.

hep-ph

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.

hep-ph

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.

hep-ph

General one-loop formulas for decay $h\rightarrow Zγ$

Radiative corrections to the $h\rightarrow Zγ$ are evaluated in the one-loop approximation. The unitary gauge gauge is used. The analytic result is expressed in terms of the Passarino-Veltman functions. The calculations are applicable for the Standard Model as well for a wide class of its gauge extensions. In particular, the decay width of a charged Higgs boson $H^\pm \rightarrow W^\pmγ$ can be derived. The consistence of our formulas and several specific earlier results is shown.

hep-ph

Decay of standard model-like Higgs boson $h\rightarrow μτ$ in a 3-3-1 model with inverse seesaw neutrino masses

By adding new gauge singlets of neutral leptons, the improved versions of the 3-3-1 models with right-handed neutrinos have been recently introduced in order to explain recent experimental neutrino oscillation data through the inverse seesaw mechanism. We prove that these models predict promising signals of lepton-flavor-violating decays of the standard-model-like Higgs boson $h^0_1\rightarrow μτ,eτ$, which are suppressed in the original versions. One-loop contributions to these decay amplitudes are introduced in the unitary gauge. Based on a numerical investigation, we find that the branching ratios of the decays $h^0_1\rightarrowμτ,eτ$ can reach values of $10^{-5}$ in the regions of parameter space satisfying the current experimental data of the decay $μ\rightarrow eγ$. The value of $10^{-4}$ appears when the Yukawa couplings of leptons are close to the perturbative limit. Some interesting properties of these regions of parameter space are also discussed.

hep-ph