arXiv subjects

A. E. Cárcamo Hernández

Publications and source records attributed to A. E. Cárcamo Hernández.

At least 19 recordsLinked to original sources

arXiv2026

Multi-component Dark Matter in a Novel Three-Loop Inverse Scotogenic Seesaw Model

We consider a model which provides an explanation of the origin of light neutrino masses, the baryon asymmetry of the Universe -- via leptogenesis -- and explains the observed dark matter relic abundance with several components. In this scenario, Majorana masses of the active neutrinos are produced by the inverse seesaw (ISS) mechanism with the lepton-number-violating mass parameter being dynamically generated at three loops with a novel topology. This model is based on an extension of the Standard Model gauge symmetry by a global $U(1)'$ and a discrete $\mathbb{Z}_2\otimes \mathbb{Z}_3$. The latter, which is responsible for the radiative origin of the ISS lepton-number-violating parameter, survives the spontaneous breaking of the global $U(1)'$ and, at the same time, ensures the stabilization of the dark sector. The lightest particles carrying non-trivial residual charges are stable, becoming potentially viable dark matter candidates. The model complies with bounds and constraints from neutrino data, collider and high-intensity charged lepton flavor-violating observables, as well as dark matter relic density and direct detection. To efficiently explore the model's high-dimensional parameter space and identify phenomenologically viable regions, we perform a global numerical scan using the MultiNest algorithm.

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arXiv2026

A novel two loop inverse seesaw model

We propose a Standard Model (SM) extension where neutrinos get masses through a two-loop inverse seesaw mechanism. This naturally explains the smallness of the neutrino masses and allows seesaw mediators to be at the TeV scale with testable phenomenology. The model adds two real singlet scalars and four electrically neutral leptons to the SM. The extension considers the existence of two global Abelian symmetries, a continuous $U(1)$ and a discrete $Z_3$. The latter, remains unbroken after spontaneous symmetry breaking and forbids tree-level and one-loop neutrino masses, and stabilizes the dark matter (DM) candidates. This setup accommodates neutrino-oscillation data, yields two pseudo-Dirac heavy pairs with small active-sterile mixing, and predicts an effective Majorana mass $m_{ee}$ in the $2.1$-$4.4$ meV range for normal ordering. Charged-lepton flavor violation is naturally suppressed yet testable: for a representative benchmark we obtain BR$(μ\to e γ)\simeq 1.6 \times 10^{-14}$, with correlated signals in $μ\to eee$ and $μ$-$e$ conversion within next-generation experimental reach. Altogether, the radiative origin of neutrino masses links low-energy flavor observables to collider signatures, delineating discovery targets for MEG II, Mu2e/COMET, and the HL-LHC and distinguishing this framework from conventional inverse- and radiative-seesaw models. Moreover, the $Z_3$ guarantees a stable DM candidate, either scalar ($ρ$) or fermionic ($Ω$). Then, here we analyze and identify the viable parameter space that is consistent with the observed DM relic abundance for both situations.

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arXiv2026

Two-loop neutrino mass model with modular $S_4$ symmetry

We propose a two-loop radiative neutrino mass model based on the modular $Γ_4 \simeq S_4$ flavour symmetry supplemented by a discrete $Z_3$ symmetry. After spontaneous modular symmetry breaking, a remnant $Z_2$ symmetry guarantees both the radiative origin of active neutrino masses and stabilizes dark matter candidates. The model successfully reproduces charged lepton masses and neutrino oscillation data for normal ordering. It also predicts observable rates for charged lepton flavour violation (LFV). Due to the singlet-doublet mixing the model provides a viable scalar dark matter candidate. A fermionic dark matter candidate, strongly linked to LFV, is also present. We identify parameter regions consistent with relic density, LFV constraints, and direct detection limits, providing testable benchmark configurations.

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arXiv2026

Dirac neutrinos and gauged lepton number

We propose the first scotogenic neutrino mass model with gauged lepton number $U(1)_L$, which is spontaneously broken by three units $ΔL=3$ down to a residual discrete gauge symmetry $\mathbb{Z}_6$. The latter guarantees that neutrinos acquire tiny Dirac masses via a one-loop scotogenic mechanism, simultaneously stabilizing the lightest electrically neutral particle with non-trivial charge under the preserved $\mathbb{Z}_6$ symmetry. In our model there is a scalar particle identified as weakly interacting massive particle dark matter (DM) candidate. We analyzed its compatibility with the existing data on direct DM detection experiments and the DM relic abundance. We also address charged lepton flavor violating decays in our model and find that their predicted rates are within the reach of current experimental sensitivity.

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arXiv2026

Extended IDM theory with low scale seesaw mechanisms

We have developed an extension of the inert doublet model in which the CP-phases in the weak sector are generated from one-loop level corrections mediated by dark fields, while the strong-CP phase arises at three-loop. In this framework, the tiny masses of the active neutrinos are produced through a radiative inverse seesaw mechanism at a two-loop level, the masses of the first and second families of SM-charged fermions arise from a one-loop level radiative seesaw mechanism, and the third generation of SM charged fermion masses are generated at tree level. We have demonstrated that the proposed model successfully accounts for SM fermion masses and mixings. The radiative nature of the seesaw mechanisms is attributed to preserved discrete symmetries, which are required for ensuring the stability of fermionic and scalar dark matter candidates. The preserved discrete symmetries also allow for multi-component dark matter, whose annihilation processes permits to successfully reproduce the measured amount of dark matter relic abundance for an appropriate region of parameter space, which has shown to be compatible with current dark matter direct detection limits. Besides that, we explore the model's ability to explain the $95$ GeV diphoton excess observed by the CMS collaboration, showing that it readily accommodates this anomaly. We have shown that charged lepton flavor violating decays acquire rates within the current experimental sensitivity.

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arXiv2026

Cobimaximal mixing pattern from a $Δ(27)$ inverse seesaw model

We present an inverse seesaw model based on the $Δ(27)$ symmetry and Abelian discrete symmetries, which account for the mass hierarchies and, through a specific pattern of symmetry breaking, leads to viable leptonic mixing angles according to the cobimaximal mixing pattern. In the model, leptogenesis successfully accounts for the observed baryon asymmetry of the Universe for a large range of the parameter space, only for the scenario of normal neutrino mass hierarchy.

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arXiv2026

Physical implications of a double right-handed gauge symmetry

Guided by the flipping principle, we propose a novel extension of the Standard Model based on a double right-handed $U(1)$ gauge symmetry. In this framework, all left-handed fermions are neutral, while right-handed fermions of the third generation carry charges distinct from those of the first two generations. This structure naturally explains the observed Standard Model fermion mass hierarchy: the heavy masses of the third generation are generated at tree level, while the lighter masses of the first and second generations arise radiatively at the one-loop level. For the active neutrino sector, the tiny masses are generated through a combination of tree-level and two-loop seesaw mechanisms. Crucially, this approach successfully reproduces the observed neutrino mass hierarchy, with the atmospheric mass-squared difference generated at tree level and the solar neutrino mass squared difference emerging at the two-loop level. These hierarchical patterns stem from the interplay between gauge invariance and a residual parity symmetry that survives the spontaneous breaking of the extended gauge group. The same residual symmetry stabilizes a viable scalar singlet dark matter candidate, which we show can reproduce the observed relic abundance while remaining consistent with current direct detection bounds. After addressing constraints from electroweak precision tests and flavor-changing neutral currents, we explore the discovery prospects for the new neutral bosons at existing and future colliders, including the LEP, LHC, and a future ILC.

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arXiv2026

Dark matter and scalar sector in a novel two-loop scotogenic neutrino mass model

We propose an extended $3+1$ Higgs doublet model where the Standard Model (SM) gauge structure is enhanced by the discrete symmetry $Q_6 \times Z_2 \times Z_4$, and the fermion content is extended with right-handed Majorana neutrinos. The scalar sector, besides four $SU(2)$ doublets, incorporates multiple gauge-singlet scalars. In our model, the tiny active neutrino masses arise from a novel radiative seesaw mechanism at two-loop level and the leptonic mixing features the cobimaximal mixing pattern compatible with neutrino oscillation experimental data. Along with this, the proposed model is consistent with SM quark masses and mixings as well as with the constraints arising from dark matter relic density and dark matter direct detection. Our analysis reveals that the best-fit point satisfying dark matter constraints yields a non-SM scalar with mass near $95$ GeV, which could be a possible candidate for the observed $95$ GeV diphoton excess. We further obtain other non SM scalars with masses at the subTeV scale which are within the LHC reach, while successfully complying with the experimental bounds arising from collider searches.

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arXiv2025

Tri-hypercharge versus tri-darkcharge

We propose a minimal, ultraviolet-complete, and renormalizable extension of the Standard Model, in which the three generations of ordinary fermions are distinguished by family-dependent hypercharges, while three right-handed neutrinos are separated by a dark gauge symmetry that is trivial for all Standard Model fields. This setup yields a fully flipped inert doublet model. The model naturally realizes a hybrid scotoseesaw mechanism that accounts for the smallness of neutrino masses and the largeness of lepton mixing. Simultaneously, it explains the stability and relic abundance of dark matter through a residual dark parity and addresses the hierarchies of charged fermion masses and the suppression of quark mixing via higher-dimensional operators involving high-scale scalar singlets and vector-like fermions. We explore the phenomenological implications of the model and derive constraints from electroweak precision tests, collider searches, flavor-changing processes, and observations of dark matter.

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arXiv2025

Strongly coupled inert scalar sector with radiative neutrino masses

We explore the phenomenological consequences of a model with an extended scalar sector, incorporating strongly coupled inert Higgs doublets. The model introduces three Higgs doublets: one that interacts with the $SU(2)$ symmetry of the Standard Model, and two inert doublets belonging to a strongly interacting sector, embedded in the $SU(2)_2 \times SU(2)_1 \times U(1)_Y$ electroweak gauge symmetry. This symmetry structure is further supplemented by a spontaneously broken $\mathbb{Z}_2$ and a preserved $\mathbb{Z}_2'$ discrete symmetry. Our approach harnesses the exotic scalar fields emerging from this sector to implement mass-generation mechanisms. In particular, a one-loop seesaw mechanism accounts for the smallness of neutrino masses, while a universal seesaw mechanism naturally explains the hierarchy of charged fermion masses below the top quark mass. The model is shown to be consistent with current experimental constraints, including those from charged lepton flavor violation, electroweak precision observables, the Higgs diphoton decay rate, and the Higgs trilinear self-coupling. Notably, it also provides a viable interpretation of the 95~GeV diphoton excess, offering a distinctive signature of new physics beyond the Standard Model.

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arXiv2025

Fermion masses and mixings and charged lepton flavor violation in a 3-3-1 model with inverse seesaw

We present a extension of the 3-3-1 gauge model supplemented by an $A_4$ flavor symmetry and cyclic discrete symmetries, including $Z_2$, $Z_2'$, $Z_3$, $Z_4$, $Z_7$ and $Z_{10}$. The model successfully reproduces the observed SM fermion mass hierarchies and mixing patterns in quark and lepton sectors. The smallness of the active neutrino masses is explained through an inverse seesaw mechanism, enabled by the introduction of right-handed and sterile Majorana neutrinos. In the quark sector, flavor-changing neutral currents (FCNCs) arise at tree level exclusively for up-type quarks via the new heavy neutral gauge boson exchange, leading to strong constraints from $D^0$ - $\bar{D}^0$ mixing. The charged lepton sector exhibits sizeable flavor-violating effects, especially in the $μ\rightarrow e γ$ decay, mediated by loops involving heavy neutrinos, new charged gauge bosons as well as charged scalars. We perform a detailed numerical fit of fermion masses and mixing parameters and identify viable regions of parameter space consistent with experimental data on CKM and PMNS mixing matrices. The model predicts branching ratios for charged lepton flavor violating decays and $μ$-$e$ conversion rates within the sensitivity of future experiments.

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arXiv2025

Modular $S_{3}$ flavoured Pati-Salam model with two family seesaw

We present a unified model of quarks and leptons with modular $S_3$ flavour symmetry, where the two lightest family masses are naturally suppressed via a Pati-Salam version of the type I seesaw mechanism, mediated through heavier vector-like fermions. Majorana neutrino masses are further suppressed through a double seesaw mechanism. The viable parameter space has a preferred range of the modulus field with Im$(τ) \sim 2 $, leading to successful fermion masses and mixing. The prediction for neutrinoless double beta decay is partly within the reach of the nEXO experiment. In particular, the Dirac CP violating neutrino oscillation phase is predicted to lie in the range $δ_{\rm CP}^ν\sim 260^o-360^o$.

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arXiv2024

Phenomenology of extended multiHiggs doublet models with $S_4$ family symmetry

We propose extended 3HDM and 4HDM models where the SM gauge symmetry is enlarged by the spontaneously broken $S_4$ group, the preserved $Z_2$ and broken $Z_4$ cyclic symmetries. Each model has three active $SU(2)$ scalar doublets, in addition, the first one has an extra inert scalar singlet, whereas the second model has an inert scalar doublet. Furthermore, each model has several extra gauge singlet scalars, which are triplets under $S_4$. Both models yield the same structure of the mass matrices for the fermion sector, where a radiative seesaw generates the tiny light active neutrinos masses at one-loop level, through the $S_4$ triplets. The presence of flavor changing neutral currents mediated by heavy scalars allowed us to study the $(K^0-\overline{K}^0)$ and $(B_{d,s}^0-\overline{B}_{d,s}^0)$ meson mixings, in the parameter space that currently satisfies the experimental constraints. On the other hand, due to the preserved $Z_2$ symmetry, our proposed models have stable scalar and fermionic dark matter candidates. Furthermore, these models are consistent with the current pattern of SM fermion masses and mixings, with the measured dark matter relic abundance and successfully accommodate the constraints arising from meson oscillations and oblique parameters. The extra scalars in our models provide radiative corrections to the oblique parameters, where due to the presence of the scalar inert doublet, renders the 4HDM less restrictive than the 3HDM one.

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arXiv2024

Phenomenology of an Extended $1+2$ Higgs Doublet Model with $S_3$ Family Symmetry

In order to explain the mass hierarchy and mixing pattern in the leptonic sector, we explore an extension of the Standard Model whose scalar sector includes one active and two inert doublets as well as some scalar singlets. The model includes a $S_3$ family symmetry supplemented by extra cyclic symmetries. As a consequence of our construction, a Dark Matter (DM) candidate is predicted and its properties are consistent with the observed cosmic abundances and the constraints imposed by direct and indirect detection experiments. The model allows Charged Lepton Flavor Violation (CLFV) processes like $μ\rightarrow eγ$ and $μ\rightarrow 3e$, but the predicted branching ratios align with experimental limits. Additionally, our analysis elucidates the generation of the active neutrino masses through a one-loop radiative seesaw mechanism matching the observed neutrino oscillation data. The model agrees with experimental data on Higgs Diphoton decay rates and on oblique parameters.

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arXiv2024

Fermion masses and mixings and $g-2$ muon anomaly in a $Q_6$ flavored 2HDM

We propose an extended 2HDM with $Q_6\times Z_4\times Z_2$ symmetry that can successfully accommodate the SM fermion mass and mixing hierarchy. The tiny masses of the active neutrinos are generated from a type-I seesaw mechanism mediated by very heavy right-handed Majorana neutrinos. The model gives a natural explanation of the charged lepton mass hierarchy. Besides that, the experimental values of the physical observables of the neutrino sector: the neutrino mass squared splittings, the leptonic mixing angles and the leptonic Dirac CP violating phase, are also successfully reproduced for both normal and inverted neutrino mass hierarchies. We find a feasible range of values for the leptonic Dirac CP phase to be in the ranges $δ_{CP}\in (305.90, 348.70)^\circ$ for normal ordering and $δ_{CP}\in (308.00, 348.00)^\circ$ for inverted ordering, which is consistent with the 3$σ$ experimentally allowed limits. The sum of neutrino masses is obtained as $\sum m_i \in (58.03, 60.51)$ meV for normal ordering and $\sum m_i\in (98.07, 101.40)$ meV for inverted ordering which are well consistent with all the recent limits. In addition, the obtained ranges for the effective neutrino masses are $\langle m_{ee}\rangle \in (3.80, 4.38)$\, meV, $m_β \in (8.53, 9.34)\, \mbox{meV}$ for normal ordering and $\langle m_{ee}\rangle \in (47.85, 49.58) $ meV, $m_β \in (48.39, 50.09)\, \mbox{meV}$ for inverted ordering which are in agreement with the recent experimental bounds. For the quark sector, the derived results are also in agreement with the recent data on the quark masses and mixing angles. The model under consideration can also accommodate the muon anomalous magnetic moment.

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arXiv2024

Effective interactions for the SM fermion mass hierarchy and their possible UV realization

We built an extended 2HDM theory with a spontaneously broken $U(1) _{X}$ global symmetry, where the tree level Universal Seesaw Mechanism generates the mass hierarchy of the Standard Model charged fermions and the Zee-Babu mechanism produces tiny active neutrino masses. The third family of SM charged fermions gets tree level masses from Yukawa interactions involving the Higgs doublets $H_1$ (for the top quark) and $H_2$ (for the bottom quark and tau lepton). The model under consideration is consistent with SM fermion masses and mixings, with the muon and electron $g-2$ anomalies and successfully accommodates the constraints arising from charged lepton flavor violation and meson oscillations. The proposed model predicts rates for charged lepton flavor violating decays within the reach of forthcoming experiments.

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arXiv2024

A common framework for fermion mass hierarchy, leptogenesis and dark matter

In this work, we explore an extension of the Standard Model designed to elucidate the fermion mass hierarchy, account for the dark matter relic abundance, and explain the observed matter-antimatter asymmetry in the universe. Beyond the Standard Model particle content, our model introduces additional scalars and fermions. Notably, the light active neutrinos and the first two generations of charged fermions acquire masses at the one-loop level. The model accommodates successful low-scale leptogenesis, permitting the mass of the decaying heavy right-handed neutrino to be as low as 10 TeV. We conduct a detailed analysis of the dark matter phenomenology and explore various interesting phenomenological implications. These include charged lepton flavor violation, muon and electron anomalous magnetic moments, constraints arising from electroweak precision observables, and implications for collider experiments.

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arXiv2024

Models of radiative linear seesaw with electrically charged mediators

We propose two versions of radiative linear seesaw models, where electrically charged scalars and vector-like leptons generate the Dirac neutrino mass submatrix at one and two loop levels. In these models, the SM charged lepton masses are generated from a one loop level radiative seesaw mechanism mediated by charged exotic vector-like leptons and electrically neutral scalars running in the loops. These models can successfully accommodate the current amount of dark matter and baryon asymmetries observed in the Universe, as well as the muon anomalous magnetic moment.

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