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T. D. Tham

Publications and source records attributed to T. D. Tham.

6 recordsLinked to original sources

$(g-2)_{\ell}$ 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

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

Phenomenology of the simple 3-3-1 model with inert scalars

The simple 3-3-1 model that contains the minimal lepton and minimal scalar contents is detailedly studied. The impact of the inert scalars (i.e., the extra fundamental fields that provide realistic dark matter candidates) on the model is discussed. All the interactions of the model are derived, in which the standard model ones are identified. We constrain the standard model like Higgs particle at the LHC. We search for the new particles including the inert ones, which contribute to the $B_s$-$\bar{B}_s$ mixing, the rare $B_s\rightarrow μ^+μ^-$ decay, the CKM unitarity violation, as well as producing the dilepton, dijet, diboson, diphoton, and monojet final states at the LHC.

hep-ph

Total cross-section for photon-axion conversions in external electromagnetic field

We reconsider the conversion of the photon into axion in the external electromagnetic fields, namely in the static fields and in a periodic field of the wave guide. The total cross-sections for the conversion are evaluated in detail. The result shows that with strong strength of external electromagnetic fields, the cross-sections are large enough to measure the axion production. In the wave guide there exists the resonant conversion at the low energies, in which the value of cross-sections is much enhanced

hep-ph

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.

hep-ph

Radion production in gamma-electron collisions

We analyze the potential of Compact Linear Colliders based on the γ-e collisions to search for the radion in the Randall-Sundrum model, where compactification radius of the extra dimension is stabilized by the radion, which is a scalar field lighter than the graviton Kaluza-Klein states. The radion production in the high energy γ-e colliders with the polarization of the electron beams are calculated in detail. Numerical evaluation shows that if the radion mass is not too heavy with the mass order of GeV then the reaction can give observable cross section in future colliders at the high degree of polarization.

hep-ph