arXiv subjects

Phung Van Dong

Publications and source records attributed to Phung Van Dong.

At least 19 recordsLinked to original sources

arXiv2026

A Minimal Dark $U(1)_D$ Framework for Inverse Seesaw Neutrino Masses and Dark Matter

We propose a minimal framework based on a dark $U(1)_D$ gauge symmetry that simultaneously accounts for neutrino masses and dark matter within an inverse seesaw realization. In this setup, the smallness of light neutrino masses is controlled, suppressed by a lepton-number violating parameter $μ$, which arises dynamically by dark field corrections rather than being introduced by hand. The limit $μ\to 0$ restores lepton number symmetry, ensuring its, thus neutrino mass, smallness in the sense of 't Hooft naturalness. We analyze the neutrino mass matrix and active-sterile mixing, highlighting their impact on non-unitarity and charged lepton flavor violation. The model is consistent with current experimental constraints while allowing potentially observable signals, such as $μ\to e γ$. The dark $U(1)_D$ symmetry stabilizes the dark matter candidate and links the neutrino and dark sectors. Viable parameter regions satisfying dark matter relic density, direct detection, and collider bounds are identified. This framework provides a minimal and predictive realization of neutrino mass generation and dark matter stability with a naturally small $μ$ parameter.

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arXiv2026

Twin hypercharges

It is shown that a duplication of the hypercharge, which is identical for the normal sector but different for the dark sector, may manifestly address neutrino mass and dark matter.

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arXiv2026

Embedding light dark matter and small neutrino mass in the flipped standard model

We revisit the flipped standard model where a $U(1)_N$ gauge group is added, determining a dark charge through the weak isospin such as $D=T_3+N$, analogous to the electric charge and hypercharge relation. We find %discover that neutrino masses are appropriately generated by a radiative inverse seesaw mechanism mediated by dark fields. Dark matter candidate is a naturally light fermion with the mass radiatively induced at the keV scale. The residual $Z_2$ parity arising from $U(1)_N$ symmetry breaking both stabilizes the dark matter candidate and prevents its potential mixing with neutrinos. Such residual $Z_2$ parity also guarantees the radiative nature of the inverse seesaw mechanism responsible for light active neutrino mass generation. It is noted that the keV dark matter may be thermally produced in the early Universe as decoupled but being still relativistic and typically overpopulated due to $U(1)_N$ portal interactions. To achieve the correct abundance, the excessive thermal production is counterbalanced by sufficient late-time entropy generation from the decay of long-lived particles. The parameter space under consideration can simultaneously accommodate the observational data from cosmic inflation and keV dark matter.

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arXiv2026

Quasi-Dirac fermion: A source of neutrino mass and dark matter

Neutral vectorlike fermion as inspired by unified theories might become quasi-Dirac states at TeV due to a violation in lepton-like symmetry. It is shown that such quasi-Dirac fermions can properly achieve radiative neutrino mass generation and dark matter stability. Indeed, the small splitting of quasi-Dirac masses, i.e. $ΔM/M\ll 1$, suitably suppresses neutrino mass to be small in order to allow dark matter annihilation and detection to be appropriate to experiment as well as charged lepton flavor violation limit.

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arXiv2025

Implications of a dark grand unification

Given that dark matter and normal matter are nontrivially unified in a grand unified theory, called dark grand unification, we derive novel residual theories at low energy explaining dark matter and neutrino mass. The first chain of which is $E_6\to SU(3)_C\otimes SU(3)_L\otimes SU(3)_R$, which contains a matter parity by itself stabilizing a dark matter candidate and producing neutrino mass via a seesaw. The second chain is $\mathrm{Trinification}\to SU(3)_C \otimes SU(3)_L\otimes U(1)_X\otimes U(1)_N$, which results in a novel family-universal 3-3-1-1 model, opposite to the normal 3-3-1-1 (or corresponding 3-3-1) model. Surprisingly, it is a variant of both minimal 3-3-1 model and 3-3-1 model with right-handed neutrinos since both $e_R$ and $ν_R$ are located at the bottoms of lepton triplets. Since this universal 3-3-1-1 model is properly embedded in the trinification, the above matter parity works governing dark matter stability as well as suppressing unwanted fermion mixings. Further, neutrino masses are naturally generated by a canonical seesaw combined with a scotogenic scheme.

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arXiv2025

Scotoseesaw mechanism from a $Z_3$ symmetry of matter

We show that the neutrino mass generation and the dark matter stability can be governed by the center of the QCD group, which is a $Z_3$ group. Three right-handed neutrinos $N_{1,2,3R}$ transform under $Z_3$ as $1,w,w^2$, where $w=e^{i2π/3}$ is the cube root of unity, and they couple to usual lepton doublets via the usual Higgs doublet $H$ and two new scalar doublets $η,χ$, which transform under $Z_3$ as $1,w^2,w$, respectively. This leads to a scotoseesaw mechanism in which the seesaw and scotogenic neutrino mass generations are induced by the Majorana $N_{1R}$ mass and the Dirac $N_{2,3R}$ mass, respectively. Although the lightest of the $Z_3$ fields is stabilized, responsible for dark matter, the model lacks an explanation for relic density and/or direct detection. The issue can be solved in a $U(1)_{B-L}$ gauge completion of the model, for which the center of the QCD group is isomorphic to $Z_3=\{1,T,T^2\}$ for $T=w^{3(B-L)}$.

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arXiv2025

Dark symmetry implication for right-handed neutrinos

We argue that the long-standing issues of neutrino mass and dark matter can be manifestly solved in a dark gauge symmetry $U(1)_D$ that transforms nontrivially only for three right-handed neutrinos $ν_{1,2,3R}$ -- the counterparts of known left-handed neutrinos. This theory assigns $ν_{1,2,3R}$ dark charge to be $D=0$, $-1$, and $+1$, respectively, in order for anomaly cancelation. Additionally, it imposes an inert Higgs doublet $η$ and two Higgs singlets $ξ,ϕ$ with dark charge $D=+1$, $-1$, and $+2$, respectively. That said, the dark symmetry is broken by $ϕ$ (by two units) down to a dark parity $P_D=(-1)^D$, for which $ν_{2,3R}$ and $η,ξ$ are odd, whereas all other fields are even due to $D=0$. The lightest of these odd fields is stabilized by $P_D$, responsible for dark matter. Neutrino masses are generated by a scotoseesaw scheme, in which the seesaw part is mediated by $ν_{1R}$, while the scotogenic part is mediated by $ν_{2,3R}$, for which the hierarchy of atmospheric and solar neutrino mass splittings is explained.

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arXiv2025

Scoto-seesaw model implied by flavor-dependent Abelian gauge charge

Assuming fundamental fermions possess a new Abelian gauge charge that depends on flavors of both quark and lepton, we obtain a simple extension of the Standard Model, which reveals some new physics insights. The new gauge charge anomaly cancellation not only explains the existence of just three fermion generations as observed but also requires the presence of a unique right-handed neutrino $ν_R$ with a non-zero new gauge charge. Further, the new gauge charge breaking supplies a residual matter parity, under which the fundamental fermions and $ν_R$ are even, whereas a right-handed neutrino $N_R$ without the new charge is odd. Consequently, light neutrino masses in our model are generated from the tree-level type-I seesaw mechanism induced by $ν_R$ and from the one-loop scotogenic contribution accommodated by potential dark matter candidates, $N_R$ and dark scalars, odd under the matter parity. We examine new physics phenomena related to the additional gauge boson, which could be observed at colliders. We analyze the constraints imposed on our model by current experimental limits on neutrino masses, neutral meson oscillations, $B$-meson decays, and charged lepton flavor violating processes. We also investigate the potential dark matter candidates by considering relic density and direct detection.

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arXiv2024

Scotoseesaw model implied by dark right-handed neutrinos

We find a dark gauge symmetry $U(1)_D$ that transforms nontrivially only for three right-handed neutrinos, $ν_{1,2,3R}$. The anomaly cancellation demands that they have a dark charge $D=0,-1,+1$ assigned to $ν_{1,2,3R}$, respectively. The dark charge is broken by two units down to a dark parity, i.e. $U(1)_D\to P_D=(-1)^D$, which stabilizes a dark matter candidate. Interestingly, the model manifestly supplies neutrino masses via joint seesaw and scotogenic mechanisms, called scotoseesaw.

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arXiv2024

Flavor-changing phenomenology in a $U(1)$ model

We investigate a family-nonuniversal Abelian extension of hypercharge, which significantly alters the phenomenological features of the standard model. Anomaly cancellation requires that the third quark family transforms differently from the first two quark families. Additionally, it acquires that three right-handed neutrinos are presented. This model generates naturally small neutrino masses and a $W$-boson mass deviation appropriate to recent measurements. Additionally, the model introduces flavor-changing neutral currents (FCNCs) of quarks coupled to the new gauge boson $Z'$ and new Higgs fields. These FCNCs significantly modify the neutral-meson mixing amplitudes and rare meson decays, which are studied in detail. We also address flavor changing processes in the charged lepton sector.

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arXiv2024

Scotogenic model from an extended electroweak symmetry

We argue that the higher weak isospin $SU(3)_L$ manifestly unifies dark matter and normal matter in its isomultiplets for which dark matter carries a conserved dark charge while normal matter does not. The resultant gauge symmetry is given by $SU(3)_C\otimes SU(3)_L \otimes U(1)_X\otimes U(1)_G$, where the first factor is the color group, while the rest defines a theory of scotoelectroweak in which $X$ and $G$ determine electric charge $Q=T_3-1/\sqrt{3}T_8+X$ and dark charge $D=-2/\sqrt{3}T_8+G$. This setup provides both appropriate scotogenic neutrino masses and dark matter stability as preserved by a residual dark parity $P_D=(-1)^D$. Interpretation of the dark charge is further discussed, given that $SU(3)_L$ is broken at very high energy scale.

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arXiv2024

Questions of flavor physics and neutrino mass from a flipped hypercharge

The flavor structure of quarks and leptons is not yet fully understood, but it hints a more fundamental theory of non-universal generations. We therefore propose a simple extension of the Standard Model by flipping (i.e., enlarging) the hypercharge $U(1)_Y$ to $U(1)_X\otimes U(1)_N$ for which both $X$ and $N$ depend on generations of both quark and lepton. By anomaly cancellation, this extension not only explains the existence of just three fermion generations as observed but also requires the presence of a right-handed neutrino per generation, which motivates seesaw neutrino mass generation. Furthermore, in its minimal version with a scalar doublet and two scalar singlets, the model naturally generates the measured fermion-mixing matrices while it successfully accommodates several flavor anomalies observed in the neutral meson mixings, $B$-meson decays, lepton-flavor-violating processes of charged leptons, as well as satisfying constraints from particle colliders.

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arXiv2024

Scotogenic gauge mechanism for neutrino mass and dark matter

Scotogenic is a scheme for neutrino mass generation through the one-loop contribution of an inert scalar doublet and three sterile neutrinos. This work argues that such inert scalar doublet is a Goldstone boson mode associated with a gauge symmetry breaking. Hence, the resultant scotogenic gauge mechanism is very predictive, generating neutrino mass as contributed by a new gauge boson doublet that eats such Goldstone bosons. The dark matter stability is manifestly ensured by a matter parity as residual gauge symmetry for which a vector dark matter candidate is hinted.

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arXiv2024

Novel imprint of a dark photon from the 3-3-1-1 model

We investigate a dark photon that arises from the UV model based upon $SU(3)_C\otimes SU(3)_L\otimes U(1)_X \otimes U(1)_G$ (3-3-1-1) gauge symmetry, where the last three factors enlarge the electroweak symmetry encompassing electric charge $Q=T_3 - 1/ \sqrt{3}T_8 +X$ and dark charge $D = -2/\sqrt{3} T_8 +G$. It is well-established that this model addresses the questions of family number, neutrino mass, and dark matter. It is shown in this work that if the 3-3-1-1 breaking scale is much bigger than the dark charge breaking scale, the relevant dark gauge boson $Z'$ is uniquely imprinted at TeV, avoiding dangerous FCNC processes, obeying precision electroweak measurements, as well as contributing to collider phenomena, even if no kinetic mixing is presented. The dark matter observables are perhaps governed by the dark charge breaking Higgs field instead of the dark photon.

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arXiv2023

Interpreting dark matter solution for $B-L$ gauge symmetry

It is shown that the solution for $B-L$ gauge symmetry with $B-L=-4,-4,+5$ assigned for three right-handed neutrinos respectively, reveals a novel scotogenic mechanism with implied matter parity for neutrino mass generation and dark matter stability. Additionally, the world with two-component dark matter is hinted.

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arXiv2023

Flavor-dependent $U(1)$ extension inspired by lepton, baryon and color numbers

There is no reason why the gauge symmetry extension is family universal as in the standard model and the most well-motivated models, e.g. left-right symmetry and grand unification. Hence, we propose a simplest extension of the standard model -- a flavor-dependent $U(1)$ gauge symmetry -- and find the new physics insight. For this aim, the $U(1)$ charge, called $X$, is expressed as $X=x B+y L$ in which $x$ and $y$ are free parameters as functions of flavor index, e.g. for a flavor $i$ they take $x_i$ and $y_i$ respectively, where $B$ and $L$ denote normal baryon and lepton numbers. Imposing a relation involved by the color number $3$, i.e. $-x_{1,2,\cdots,n}=x_{n+1,n+2,\cdots,n+m}=3y_{1,2,\cdots,n+m}\equiv 3z$, for arbitrarily nonzero $z$, we achieve a novel $U(1)$ theory with implied $X$-charge. This theory not only explains the origin of the number of observed fermion families but also offers a possible solution for both neutrino mass and dark matter, which differs from $B-L$ extension. Two typical models based on this idea are examined, yielding interesting results for flavor-changing neutral currents and particle colliders, besides those of neutrino mass and dark matter.

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arXiv2023

Phenomenology of a minimal extension of the standard model with a family-dependent gauge symmetry

We consider a gauge symmetry extension of the standard model given by $SU(3)_C\otimes SU(2)_L\otimes U(1)_X\otimes U(1)_N\otimes Z_2$ with minimal particle content, where $X$ and $N$ are family dependent but determining the hypercharge as $Y=X+N$, while $Z_2$ is an exact discrete symmetry. In our scenario, $X$ (while $N$ is followed by $X-Y$) and $Z_2$ charge assignments are inspired by the number of fermion families and the stability of dark matter, as observed, respectively. We examine the mass spectra of fermions, scalars, and gauge bosons, as well as their interactions, in presence of a kinetic mixing term between $U(1)_{X,N}$ gauge fields. We discuss in detail the phenomenology of the new gauge boson and the right-handed neutrino dark matter stabilized by $Z_2$ conservation. We obtain parameter spaces simultaneously satisfying the recent CDF $W$-boson mass, electroweak precision measurements, particle colliders, as well as dark matter observables, if the kinetic mixing parameter is not necessarily small.

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arXiv2023

Can the Higgs field feel a dark force?

We argue that if an electroweak Higgs field possesses a dark gauge charge responsible for dark matter stability, the $W$-boson mass deviation is properly induced, besides appropriately generated neutrino masses. We examine a simple model in which the usual Higgs doublet plays the role but dark matter candidates are somewhat input by ad hoc. We look for a realistic model that fully realizes such observation, thereby neutrino mass and dark matter are naturally supplied by a dark non-abelian gauge symmetry.

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