arXiv subjects

Myriam Mondragón

Publications and source records attributed to Myriam Mondragón.

17 recordsLinked to original sources

arXiv2026

Quark Mixing Model with Three Higgs Doublets and $S_3$ Modular Symmetry at $τ=i$

We study the quark sector of a model with three Higgs electroweak doublets, complemented with a modular $S_3$ symmetry. We show that a proper assignment of the quark and Higgs fields in $S_3$ and their modular weights allows to write a mass matrix with a phenomenologically viable texture. Moreover, by considering the conditions on the Higgs VEVs derived from the minimization of the scalar potential together with evaluation of the Yukawa couplings at the fixed point $τ=i$, leads to a significant reduction of the free parameters. We present two setups, one with three effective parameters, which is overly constrained, and one with four effective parameters, where the $V_{CKM}$ matrix can be fitted precisely.

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arXiv2026

Emergence of conformal properties in Finite Grand Unified Theories via reduction of couplings

Zimmermann's Reduction of Couplings (RoC) method is a powerful tool for addressing the problem of the excess of parameters in a field theory, as it yields relations among couplings that are invariant under the renormalization group. Its usefulness becomes particularly evident when constructing predictive supersymmetric GUT models that are free of UV-divergences to all orders. Within this scale-invariant framework, we show that a SUSY model satisfying the conditions of all-loop finiteness exhibits a conformal regime induced by superpotential operators compatible with the RoC. In the soft-breaking sector, the method was shown to lead to a set of scale-invariant relations between the soft couplings and the parameters of the dimensionless sector, among which a sum rule for the scalar masses is particularly notable. These relations closely resemble the typical AMSB relations, while avoiding the tachyonic mass spectrum thanks to the sum rule. Based on this observation, we provide new evidence for a connection between the reduction of parameters in the dimensionful SSB sector and the emergence of an anomaly-mediated (AMSB-like) pattern, under the assumption that the finite Grand Unified Theory is connected to an effective $N=1$, $d=4$ Weyl-invariant SUGRA theory. In this process, we find that an all-order finite model with this property requires a specific form of the Kähler potential, whose structure coincides with that studied in no-scale supergravity scenarios.

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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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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

Inverse See-Saw Mechanism with $\mathbf{S}_{3}$ flavor symmetry

The current neutrino experiments provide an opportunity for testing the inverse see-saw mechanism through charged lepton flavor violating processes and neutrinoless double beta decay. Motivated by this, in this paper we study the $\mathbf{S}_{3}\otimes \mathbf{Z}_{2}$ discrete symmetry in the $B-L$ gauge model where the active light neutrino mass matrix comes from the aforementioned mechanism. In this framework, the effect of complex vacuum expectation values of the Higgs doublets on the fermion masses is explored and, under certain assumptions on the Yukawa couplings, we find that the neutrino mixing is controlled by the Cobimaximal pattern, but a sizeable deviation from the charged lepton sector breaks the well known predictions on the atmospheric angle ($45^{\circ}$) and the Dirac CP-violating phase ($-90^{\circ}$). In addition, due to the presence of heavy neutrinos at the $TeV$ scale, charged lepton flavor violation (CLFV) and neutrinoless double beta decay get notable contributions. Analytical formulae for these observables are obtained, and then a numerical calculation allows to fit quite well the lepton mixing for the normal and inverted hierarchies, however, the branching ratios decay values for CLFV disfavors the latter one. Along with this, the region of parameter space for the $m_{ee}$ effective neutrino mass lies below the GERDA bounds for both the normal and inverted hierarchies. On the other hand, with a particular benchmark, the quark mass matrices are found to have textures that allow to fit with great accuracy the CKM mixing matrix.

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arXiv2024

Flavour in $SU(5)$ Finite Grand Unified Models

Four $SU(5)$ $N=1$ supersymmetric models which exhibit $S_3$ and/or $Z_N$ symmetries are studied, that are finite to two or all loops, and their corresponding mass matrices. The first is an all-loop finite model based on an $S_3\times Z_3\times Z_2$ flavour symmetry, which leads to phenomenologically nonviable mass matrices. The remaining models, based on cyclic symmetries, show various mass textures, some of which are phenomenologically promising. For the two-loop finite models, the parametric solutions to the finiteness conditions determine completely some of the Yukawa couplings, and lead to a restricted range of values for other ones at the GUT scale, with a considerable reduction in the number of free parameters. One particular solution of the two-loop models shows an enhanced symmetry, leading to an all-loop finite model, which has a significant parameter reduction and could in principle reproduce the observed quark masses and mixing pattern. In this case the finiteness conditions determine the absolute value of all the Yukawa couplings at the unification scale. Finally, the minimum number of phases in the mass matrices and their position are determined, a task not previously done in Finite Unified Theories, which contributes towards the reduction of parameters and a better understanding of the Yukawa couplings. the Yukawa couplings.

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arXiv2022

Fermion masses and mixings, dark matter, leptogenesis and $g-2$ muon anomaly in an extended 2HDM with inverse seesaw

We propose a predictive $Q_4$ flavored 2HDM model, where the scalar sector is enlarged by the inclusion of several gauge singlet scalars and the fermion sector by the inclusion of right handed Majorana neutrinos. In our model, the $Q_4$ family symmetry is supplemented by several auxiliary cyclic symmetries, whose spontaneous breaking produces the observed pattern of SM charged fermion masses and quark mixing angles. The light active neutrino masses are generated from an inverse seesaw mechanism at one loop level thanks to a remnant preserved $Z_2$ symmetry. Our model succesfully reproduces the measured dark matter relic abundance and is consistent with direct detection constraints for masses of the DM candidate around $\sim$ 6.3 TeV. Furthermore, our model is also consistent with the lepton and baryon asymmetries of the Universe as well as with the muon anomalous magnetic moment

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arXiv2022

Scalar field dark matter with two components: combined approach from particle physics and cosmology

In this work we explore the possibility of incorporating particle physics motivated scalar fields to the dark matter cosmological model. In this landscape, we consider the classical complex scalar field in a certain region in the parameter space of the model that increases the number of neutrino species $N_{\mathrm{eff}}$, in order to be consistent with the observed abundance of light elements produced at Big Bang Nucleosynthesis (BBN). We perform analyses using one and two scalar fields. We examine the difference between these models and the priors considered at the edges of the cosmic ladder, this with the purpose of studying the impact of such models on the Hubble cosmic flow. In the two scalar field models we explore the possibility of combining an axion and a Higgs-like field as well as a Higgs-like field and the classical field, we show that in the first case there is no set of parameters that allows us to be consistent with $N_\mathrm{eff}$, while in the second case a strong restriction to the set of parameters is obtained. This last restriction is given in terms of a maximum bound of the fraction of Higgs-like field that can be incorporated together with the classical field. Our results could be relevant in the direct dark matter detection programs.

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arXiv2021

From Veltman's conditions to Finite Unification

First we review Veltman's suggestion to attack the naturalness problem in the Standard model by requiring absence of quadratic divergences and the resulting mass formula. Then we emphasise the influence of Veltman's suggestion in strengthening the belief that supersymmetry is the natural playground for solving the problem of quadratic divergences. Going further, we recall few sporadic suggestions concerning the cancellation of the logarithmic divergences too, which in the framework of supersymmetry has led to the construction of all-loop Finite Theories with the use of the idea of reduction of couplings. Eventually, we concentrate on a specific Finite Unified Theory and its successful predictions for the top and Higgs mass, among others, and the prospects of its final justification in future collider searches.

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arXiv2021

Probing Unified Theories with Reduced Couplings at Future Hadron Colliders

The search for renormalization group invariant relations among parameters to all orders in perturbation theory constitutes the basis of the reduction of couplings concept. Reduction of couplings can be achieved in certain $N=1$ supersymmetric Grand Unified Theories and few of them can become even finite at all loops. We review the basic idea, the tools that have been developed as well as the resulting theories in which successful reduction of couplings has been achieved so far. These include: (i) a reduced version of the minimal $N = 1$ $SU(5)$ model, (ii) an all-loop finite $N = 1$ $SU(5)$ model, (iii) a two-loop finite $N = 1$ $SU(3)^3$ model and finally (vi) a reduced version of the Minimal Supersymmetric Standard Model. In this paper we present a number of benchmark scenarios for each model and investigate their observability at existing and future hadron colliders. The heavy supersymmetric spectra featured by each of the above models are found to be beyond the reach of the 14 TeV HL-LHC. It is also found that the reduced version of the MSSM is already ruled out by the LHC searches for heavy neutral MSSM Higgs bosons. In turn the discovery potential of the 100 TeV FCC-hh is investigated and found that large parts of the predicted spectrum of these models can be tested, but the higher mass regions are beyond the reach even of the FCC-hh.

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arXiv2020

Updates and New Results in Models with Reduced Couplings

The idea of reduction of couplings consists in searching for renormalization group invariant relations between parameters of a renormalizable theory that hold to all orders of perturbation theory. Based on the principle of the reduction of couplings, one can construct Finite Unified Theories (FUTs) which are $N=1$ supersymmetric Grand Unified Theories that can be made all-order finite. The prediction of the top quark mass well in advance of its experimental discovery and the prediction of the light Higgs boson mass in the range $\sim 121-126$ GeV much earlier than its experimental discovery are among the celebrated successes of such models. Here, after a brief review of the reduction of couplings method and the properties of the resulting finiteness in supersymmetric theories, we analyse four phenomenologically favoured models: a minimal version of the $N=1$ $SU(5)$, a finite $N=1$ $SU(5)$, a $N=1$ finite $SU(3)\otimes SU(3)\otimes SU(3)$ model and a reduced version of the Minimal Supersymmetric Standard Model (MSSM). A relevant update in the phenomenological evaluation has been the improved light Higgs-boson mass prediction as provided by the latest version of $\texttt{FeynHiggs}$. All four models predict relatively heavy supersymmetric spectra that start just below or above the TeV scale, consistent with the non-observation LHC results. Depending on the model, the lighter regions of the spectra could be accessible at CLIC, while the FCC-hh will be able to test large parts of predicted spectrum of each model. The lightest supersymmetric particle (LSP), which is a neutralino, is considered as a cold dark matter candidate and put to test using the latest $\texttt{MicrOMEGAs}$ code.

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arXiv2019

B-L Model with ${\bf S}_{3}$ Symmetry: Nearest Neighbor Interaction Textures and Broken $μ\leftrightarrowτ$ Symmetry

We make a scalar extension of the B-L gauge model where the ${\bf S}_{3}$ non-abelian discrete group drives mainly the Yukawa sector. Motived by the large and small hierarchies among the quark and active neutrino masses respectively, the quark and lepton families are not treated on the same footing under the assignment of the discrete group. As a consequence, the Nearest Neighbor Interactions (NNI) textures appear in the quark sector, leading to the CKM mixing matrix, whereas in the lepton sector, a soft breaking of the $μ\leftrightarrow τ$ symmetry in the effective neutrino mass that comes from type I see-saw mechanism, provides a non-maximal atmospheric angle and a non-zero reactor angle.

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arXiv2019

Reduction of Couplings and its application in Particle Physics

The idea of reduction of couplings in renormalizable theories will be presented and then will be applied in Particle Physics models. Reduced couplings appeared as functions of a primary one, compatible with the renormalization group equation and thus solutions of a specific set of ordinary differential equations. If these functions have the form of power series the respective theories resemble standard renormalizable ones and thus widen considerably the area covered until then by symmetries as a tool for constraining the number of couplings consistently. Still on the more abstract level reducing couplings enabled one to construct theories with beta-functions vanishing to all orders of perturbation theory. Reduction of couplings became physics-wise truly interesting and phenomenologically important when applied to the standard model and its possible extensions. In particular in the context of supersymmetric theories it became the most powerful tool known today once it was learned how to apply it also to couplings having dimension of mass and to mass parameters. Technically this all relies on the basic property that reducing couplings is a renormalization scheme independent procedure. Predictions of top and Higgs mass prior to their experimental finding highlight the fundamental physical significance of this notion.

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arXiv2017

Neutrino masses, mixing, and leptogenesis in an S3 model

In this work we use previous results on the masses and mixing of neu- trinos of an S3 model with three right-handed Majorana neutrinos and three Higgs doublets, to reduce one parameter in the case when two of the right-handed neutrinos are mass degenerate. We derive a new param- eterization for the VP M N S mixing matrix, with a new set of parameters, in the more general case where the right-handed neutrino masses are dif- ferent. With these results, we calculate leptogenesis and the associated baryogenesis in the model in the two different scenarios. We show that it is possible to have enough leptogenesis to explain the baryonic asymmetry with right-handed neutrino masses above 10^{6} GeV.

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arXiv2016

Anapole moment of the lightest neutralino in the cMSSM

We study the anapole moment of the lightest neutralino in the constrained Minimal Supersymmetric Standard Model (cMSSM). The electromagnetic anapole is the only allowed electromagnetic form factor for Majorana fermions, such as the neutralino. Since the neutralino is the LSP in many versions of the MSSM and therefore a candidate for dark matter, its characterization through its electromagnetic properties is important both for particle physics and for cosmology. We perform a scan in the parameter space of the cMSSM and find that the anapole moment is different from zero albeit very small ($< 10^{-3}$ GeV$^{-2}$). Combined with experimental constraints like the Higgs mass and the DM relic density, the allowed region of parameter space lies within the reach of future direct DM searches. Thus, the anapole moment could be used as a complementary constraint when studying the parameter space of the cMSSM and other similar models.

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arXiv2012

Toroidal dipole moment of the lightest neutralino in the cMSSM

We study the toroidal dipole moment of the lightest neutralino in the constrained Minimal Supersymmetric Standard Model. The toroidal dipole moment is the only electromagnetic property of the neutralino. Since the neutralino is the LSP in many versions of the MSSM and therefore a candidate for dark matter, its characterization through its electromagnetic properties is important both for particle physics and for cosmology. We perform a scan in the parameter space of the cMSSM and find that the toroidal dipole moment is different from zero, albeit very small, in all the parameter space, and reaches a value around $10^{-3} \mathrm{GeV}^{-2}$ in a particular region of the parameter space, well below experimental bounds.

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arXiv2006

Entropy considerations in constraining the mSUGRA parameter space

We explore the use of two criteria to constraint the allowed parameter space in mSUGRA models. Both criteria are based in the calculation of the present density of neutralinos as dark matter in the Universe. The first one is the usual ``abundance'' criterion which is used to calculate the relic density after the ``freeze-out'' era. To compute the relic density we used the numerical public code micrOMEGAs. The second criterion applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas evaluating then the change in the entropy per particle of this gas between the ``freeze-out'' era and present day virialized structures. An ``entropy-consistency'' criterion emerges by comparing theoretical and empirical estimates of this entropy. The main objective of our work is to determine for which regions of the parameter space in the mSUGRA model are both criteria consistent with the 2$σ$ bounds according to WMAP for the relic density: $0.0945<Ω_{CDM}h^2<0.1287$. As a first result, we found that for $A_0=0$, sgn$μ=+$, small values of tan$β$ are not favored; only for tan$β\simeq50$ are both criteria significantly consistent.

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