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T. Phong Nguyen

Publications and source records attributed to T. Phong Nguyen.

At least 19 recordsLinked to original sources
arXiv2025

Neutrino phenomenology in a Standard Model extension with $\mathbf{T^\prime\times Z_{10} \times Z_2}$ symmetry

We construct a Standard Model (SM) extension with $T^\prime\times Z_{10} \times Z_2$ symmetry for generating the expected neutrino mass matrix with the relation $(M_ν)_{13}=(M_ν)_{31}=-\frac{1}{2}(M_ν)_{22}$ via the contributions of the Type-I seesaw and Weinberg-type operators. The proposed model possesses viable parameters capable of predicting the neutrino oscillation parameters being in good agreement with recent constraints. Our analysis reveals the predicted regions for the physical quantities, given as follows. The two mass squared splittings are $δm^2\in (69.360, 79.220)\, \mathrm{meV}^2$ and $Δm^2\in (2.484, 2.490)10^3\,\mathrm{meV}^2$ for normal ordering (NO) while $δm^2\in (69.450, 79.160)\, \mathrm{meV}^2$ and $Δm^2\in (-2.464, -2.456)10^3\,\mathrm{meV}^2$ for inverted ordering (IO). The lightest neutrino mass is $m_{\ell}\in (36.720, 36.780)$ meV for NO and $m_{\ell}\in (62.220,\, 62.310)$ meV for IO. The sum of neutrino mass is $\sum m_ν\in (136.700,\, 136.800)$ meV for NO and $\sum m_ν\in (221.400,\, 221.600)$ meV for IO. Two Majorana phases are predicted to be $α\in (6.367, 6.380)^\circ$ and $β\in (6.936, 6.946)^\circ$ for NO while $α\simeq 358.800^\circ$ and $β\simeq 0.600^\circ$ for IO. Finally, the effective neutrino mass is $m_{\mathrm{ee}}\in (36.940, 36.980)$ meV for NO and $m_{\mathrm{ee}}\in (76.290, 76.360)$ meV for IO. Based on these results, the Yukawa-like couplings are estimated, which can naturally explain the charged - lepton as well as neutrino mass hierarchies.

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↗
arXiv2023

One-loop contributions to decays $e_b\to e_a γ$ and $(g-2)_{e_a}$ anomalies, and Ward identity

In this paper, we will present analytic formulas to express one-loop contributions to lepton flavor violating decays $e_b\to e_a γ$, which are also relevant to the anomalous dipole magnetic moments of charged leptons $e_a$. These formulas were computed in the unitary gauge, using the well-known Passarino-Veltman notations. We also show that our results are consistent with those calculated previously in the 't Hooft-Veltman gauge, or in the limit of zero lepton masses. At the one-loop level, we show that the appearance of fermion-scalar-vector type diagrams in the unitary gauge will violate the Ward Identity relating to an external photon. As a result, the validation of the Ward Identity guarantees that the photon always couples with two identical particles in an arbitrary triple coupling vertex containing a photon.

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

hep-ph↗
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.

hep-ph↗
arXiv2022

Determining Atmospheric Electric Fields using MGMR3D

Cosmic-ray particles impinging on the atmosphere induce high-energy particle cascades in air, an Extensive Air Shower (EAS), emitting coherent radio emission. This emission is affected by the presence of strong electric fields during thunderstorm conditions. To reconstruct the atmospheric electric field from the measured radio footprint of the EAS we use an analytic model for the calculation of the radio emission, MGMR3D. In this work we make an extensive comparison between the results of a microscopic model for radio emission, CoREAS, to obtain an improved parametrization for MGMR3D in the presence of atmospheric electric fields, as well as confidence intervals. The approach to extract the electric field structure is applied successfully to an event with a complicated radio footprint measured by LOFAR during thunderstorm conditions. This shows that, with the improved parametrization, MGMR3D can be used to extract the structure of the atmospheric electric field.

astro-ph.HE↗
arXiv2022

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↗
arXiv2020

CP violations in a predictive $A_4$ symmetry model

We will investigate numerically a seesaw model with $A_4$ flavor symmetry to find allowed regions satisfying the current experimental neutrino oscillation data, then use them to predict physical consequences. Namely, the lightest active neutrino mass has order of $\mathcal{O}(10^{-2})$ eV. The effective neutrino mass $|\langle m\rangle|$ associated with neutrinoless double beta decay is in the range of $[0.002 \;\mathrm{eV},0.038\;\mathrm{eV}]$ and $[0.048\;\mathrm{eV},0.058\;\mathrm{eV}]$ corresponding to the normal and the inverted hierarchy schemes. Other relations among relevant physical quantities are shown, so that they can be determined if some of them are confirmed experimentally. The recent data of the baryon asymmetry of the Universe ($η_B$) can be explained via leptogenesis caused by the effect of the renormalization group evolution on the Dirac Yukawa couplings, provided the right handed neutrino mass scale $M_0$ is ranging from $\mathcal{O}(10^8)$ GeV to $\mathcal{O}(10^{12})$ GeV for $\tanβ=3$. This allowed $M_0$ range distinguishes with the scale of $\mathcal{O}(10^{13})$ GeV concerned by other effects that also generate the consistent $η_B$ from leptogenesis. The branching ratio of the decay $ μ\rightarrow\,eγ$ may reach the future experimental sensitivity in the very light values of $M_0$. Hence, it will be inconsistent with the $M_0$ range predicted from the $η_B$ data whenever this decay is detected experimentally.

hep-ph↗
arXiv2018

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↗
arXiv2018

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↗
arXiv2016

Lepton flavor violating decay of SM-like Higgs in a radiative neutrino mass model

The lepton flavor violating decay of the Standard Model-like Higgs (LFVHD) is discussed in the framework of the radiative neutrino mass model built in \cite{Kenji}. The branching ratio (BR) of the LFVHD are shown to reach $10^{-5}$ in the most interesting region of the parameter space shown in \cite{Kenji}. The dominant contributions come from the singly charged Higgs mediations, namely the coupling of $h^\pm_2$ with exotic neutrinos. Furthermore, if doubly charged Higgs is heavy enough to allow the mass of $h^\pm_2$ around 1 TeV, the mentioned BR can reach $10^{-4}$. Besides, we have obtained that the large values of the Br$(h\rightarrowμτ)$ leads to very small ones of the Br$(h\rightarrow eτ)$, much smaller than various sensitivity of current experiments.

hep-ph↗
arXiv2016

Lepton flavor violating decays of Standard-Model-like Higgs in 3-3-1 model with neutral lepton

The one loop contribution to the lepton flavor violating decay $h^0\rightarrow μτ$ of the SM-like neutral Higgs (LFVHD) in the 3-3-1 model with neutral lepton is calculated using the unitary gauge. We have checked in detail that the total contribution is exactly finite, and the divergent cancellations happen separately in two parts of active neutrinos and exotic heavy leptons. By numerical investigation, we have indicated that the one-loop contribution of the active neutrinos is very suppressed while that of exotic leptons is rather large. The branching ratio of the LFVHD strongly depends on the Yukawa couplings between exotic leptons and $SU(3)_L$ Higgs triplets. This ratio can reach $10^{-5}$ providing large Yukawa couplings and constructive correlations of the $SU(3)_L$ scale ($v_3$) and the charged Higgs masses. The branching ratio decreases rapidly with the small Yukawa couplings and large $v_3$.

hep-ph↗
arXiv2013

The 3-3-1 model with inert scalar triplet

We show that the typical 3-3-1 models are only self-consistent if they contain interactions explicitly violating the lepton number. The 3-3-1 model with right-handed neutrinos can by itself work as an economical 3-3-1 model as a natural recognition of the above criteria while it also results an inert scalar triplet (η) responsible for dark matter. This is ensured by a Z_2 symmetry (assigned so that only ηis odd while all other multiplets which perform the economical 3-3-1 model are even), which is not broken by the vacuum. The minimal 3-3-1 model can provide a dark matter by a similar realization. Taking the former into account, we show that the dark matter candidate (H_η) contained in ηtransforms as a singlet in effective limit under the standard model symmetry and being naturally heavy. The H_ηrelic density and direct detection cross-section will get right values when the H_ηmass is in TeV range as expected. The model predicts the H_ηmass m_{H_η}=λ_5\times 2 TeV and the H_η-nucleon scattering cross-section σ_{H_η-N}=1.56\times 10^{-44} cm^2, provided that the new neutral Higgs boson is heavy enough than the dark matter.

hep-ph↗
arXiv2010

A direct link between neutrinoless double beta decay and leptogenesis in a seesaw model with $S_4$ symmetry

We study how leptogenesis can be implemented in a seesaw model with $S_4$ flavor symmetry, which leads to the neutrino tri-bimaximal mixing matrix and degenerate right-handed (RH) neutrino spectrum. Introducing a tiny soft $S_4$ symmetry breaking term in the RH neutrino mass matrix, we show that the flavored resonant leptogenesis can be successfully realized, which can lower the seesaw scale much so as to make it possible to probe in colliders. Even though such a tiny soft breaking term is essential for leptogenesis, it does not significantly affect the low energy observables. We also investigate how the effective light neutrino mass $| |$ associated with neutrinoless double beta decay can be predicted along with the neutrino mass hierarchies by imposing experimental data of low-energy observables. We find a direct link between leptogenesis and neutrinoless double beta decay characterized by $| |$ through a high energy CP phase $ϕ$, which is correlated with low energy Majorana CP phases. It is shown that our predictions of $| |$ for some fixed parameters of high energy physics can be constrained by the current observation of baryon asymmetry.

hep-ph↗