arXiv subjects

N. H. T. Nha

Publications and source records attributed to N. H. T. Nha.

11 recordsLinked to original sources

arXiv2026

Charged lepton flavor violating decays and $(g-2)_{e_a}$ in an extended standard model with singlet and triplet leptoquarks

We study the anomalous magnetic moments of charged leptons and their lepton flavor-violating decays in a Standard Model extension containing one $SU(2)_L$singlet and one $SU(2)_L$ triplet scalar leptoquark. Our results reveal significant correlations among $Δa_{e,μ}$ and the decay rates of $e_b\to e_aγ$, and $h,Z\to e_b e_a$. In particular, the branching ratios $\mathrm{Br}(e_b\to e_aγ)$ and $\mathrm{Br}(h,Z\to e_b e_a)$ exhibit significant correlations. The model cannot simultaneously accommodate sizable values of $|Δa_e|=\mathcal{O}(10^{-13})$ and $|Δa_μ|=\mathcal{O}(10^{-10})$. For $|Δa_μ|=\mathcal{O}(10^{-10})$ and $\mathrm{Br}(μ\to eγ)>10^{-15}$, the decay rates are suppressed to $\mathrm{Br}(τ\to eγ)<\mathcal{O}(10^{-12})$ and $\mathrm{Br}(h\to τe)<\mathcal{O}(10^{-6})$, while the remaining ones can reach the forthcoming experimental sensitivities. Conversely, for $|Δa_e|=\mathcal{O}(10^{-13})$, one obtains the suppressed decay rates $\mathrm{Br}(τ\to μγ)<\mathcal{O}(10^{-11})$ and $\mathrm{Br}(h\to τμ)<\mathcal{O}(10^{-7})$.

hep-ph↗

arXiv2026

$(g-2)_{\ell}$ and LFV decays in a $U(1)_{L_μ -L_τ}$ left-right model with inverse seesaw neutrinos

In the framework of a $U(1)_{L_μ -L_τ}$ left-right model with inverse seesaw neutrinos recently proposed, we show that one-loop contributions from heavy singly charged Higgs bosons to the anomalous magnetic moments of charged leptons $(g-2)_{e,μ}$ can accommodate the observed discrepancies, of $10^{-9}$ and $\mathcal{O}(10^{-13})$ for the muon and electron, respectively. Meanwhile, all lepton-flavor violating decay rates for $h\to e_b^\pm e_a^\mp $, $Z\to e_b^\pm e_a^\mp$, and $e_b\to e_a γ$ are found to be highly suppressed as a consequence of the gauged $U(1)_{L_μ-L_τ}$ symmetry.

hep-ph↗

arXiv2026

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 $μ\to eγ$ 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 $\mathrm{Br}(h,Z\to e_b^\pm e_a^\mp)\propto\mathrm{Br}(e_b\to e_aγ)$. Furthermore, the model exhibits a complementary interplay between the charged-lepton anomalous magnetic moments: parameter regions with $|Δa_μ|\geq10^{-11}$ favor $\mathrm{Br}(h,Z\toτ^\pmμ^\mp)$ reaching their current experimental upper limits while keeping $|Δa_e|$ negligible, whereas regions with $10^{-14}\leq|Δa_e|\leq 8\times10^{-13}$ instead allow $\mathrm{Br}(h,Z\toτ^\pm e^\mp)$ to approach the present experimental sensitivities but simultaneously suppress $|Δa_μ|$ to the level of $\mathcal{O}(10^{-16})$.

hep-ph↗

arXiv2026

Probing axion in the DFSZ model

We show that with the introduction of new right-handed neutrinos $N_R$, the Peccei--Quinn ($PQ$) transformation in the DFSZ (Dine--Fischler--Srednicki--Zhitnitsky) model depends only on the $PQ$ charge of the scalar singlet $ϕ$, namely $PQ_ϕ$, and is independent of the sine and cosine of $\arctan(v_u/v_d)$. The model consists of four new scalars: a charged Higgs boson $H^\pm$, a CP-odd scalar $A$, and two CP-even scalars with masses at the EW scale (of a few hundred GeV), and a superheavy inflaton $Φ$. The scalar fields have been presented in the form of unitary matrices, in which there is no mixing between the axion and the Goldstone boson $G_Z$. As a result, there are two kinds of couplings between the axion and fermions, namely Yukawa-like interactions and anomaly-induced ones associated with derivative axion couplings. {The model belongs to the DFSZ I kind since the axion - photon coupling with $\fr E N = \fr 8 3$.} The trilinear Higgs self-coupling is investigated. We have shown that, in the parameter region where new scalar fields such as the singly charged Higgs boson $H^\pm$ and the CP-odd scalar $A$ have masses around 150 GeV and the vacuum expectation value of one Higgs doublet ($v_u$) is of the order of a few GeV, the coupling modifier $κ_λ$-a probe of new physics-is consistent with the current experimental constraints.

hep-ph↗

arXiv2026

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 $(g-2)_{e,μ}$ 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$(τ\to μγ)$ imposes a stringent constraint compatible with the $1σ$ experimental range of $(g-2)_μ$, corresponding to an allowed deviation of order $10^{-9}$ from the SM prediction. The forthcoming experimental sensitivity to Br$(τ\to μγ)$ will reduce this deviation to $5\times 10^{-10}$.

hep-ph↗

arXiv2024

$(g-2)_{e,μ}$ 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↗

arXiv2024

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↗

arXiv2024

$(g-2)_{e,μ}$ 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↗

arXiv2024

$(g-2)_{e,μ}$ 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↗

arXiv2024

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

Two decay channels $h\rightarrow γγ, Zγ$ 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 $h\rightarrow Zγ$ amplitude, but not the $h\rightarrow γγ$ amplitude. From numerical investigations, we show that the signal strength $μ_{Z γ}$ of the decay $h\rightarrow Zγ$ is still constrained strictly by that of $h\rightarrow γγ$, namely $|Δμ_{γγ}|<38\%$ results in max $|Δμ_{Z γ}|<46\%$. On the other hand, the future experimental sensitivity $|Δμ_{γγ}|=4\%$ still allows $|Δμ_{Z γ}|$ reaches to values larger than the expected sensitivity $|Δμ_{Z γ}|=23\%$.

hep-ph↗

arXiv2022

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 $\mathcal{O}(10^{-4})$.

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