arXiv subjects

S. F. Mantilla

Publications and source records attributed to S. F. Mantilla.

8 recordsLinked to original sources

arXiv2026

From Peccei Quinn symmetry to mass hierarchy problem

We propose a non-universal $\mathrm{U}(1)_{X}$ gauge extension to the Standard Model (SM) and an additional Peccei-Quinn (PQ) global symmetry to study the mass hierarchy and strong CP problem. The scheme allows us to distinguish among fermion families and to generate the fermionic mass spectrum of particles of the SM. The symmetry breaking is performed by two scalar Higgs doublets and two scalar Higgs singlets, where one of these has the axion which turns out to be a candidate for Cold Dark Matter. The exotic sector is composed by one up-like $T$ and two down-like $J^{1,2}$ heavy quarks, two heavy charged leptons $E,\mathcal{E}$, one additional right-handed neutrino per family $ν_{R}^{e,μ,τ}$, and an invisible axion $a$. In addition, the large energy scale associated to the breaking of the PQ-symmetry gives masses to the right-handed neutrinos in such a way that the active neutrinos acquire eV-mass values due to the see-saw mechanism. On the other hand, from the non-linear effective Lagrangian, the flavour changing of the down quarks and charged leptons with the axion are considered.

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arXiv2026

Radiative neutrino masses in an abelian extension of the Standard Model

The seesaw mechanism is the preferred methodology to obtain light neutrino masses by the introduction of a Majorana mass matrix. Moreover, radiative corrections can be done in order to improve the predictions of the model. However, when such a Majorana mass has no inverse, radiative corrections turn out as the only mechanism to get massive neutrinos. In this letter, it is shown a nonuniversal abelian extension $\mathrm{U(1)}_{X}$ of the Standard Model in which neutrinos acquire masses completely by radiative corrections through one-loop self-energies involving heavier right-handed neutrinos. Moreover, one right-handed neutrino also gets mass through radiative corrections involving Majorana fermions. Finally, some limit cases are drafted depending on the hierarchy among vacuum expectation values and Majorana masses.

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arXiv2023

A gauged non-universal $U(1)_{X}$ model to study muon $g-2$ and $B$ meson anomalies

We study a non-universal $U(1)_{X}$ extension of the Standard Model with an extended scalar sector of two doublets and one singlet plus three additional exotic quarks and two exotic charged leptons on the fermionic sector. In order to obtain the observed fermion mass hierarchy, an additional $\mathbb{Z}_{2}$ discrete symmetry is imposed, where the heaviest fermions acquire their masses from three different scales determined by two Higgs doublets and one singlet, whereas the lightest fermions obtain their masses from effective operators up to dimension seven. From chiral anomalies cancellation, the model also includes heavy right-handed neutrinos which get massive via an inverse see-saw mechanism, reproducing the observed mass differences for the active neutrinos. We analyze phenomenological consequences of the model in view of the so-called flavour anomalies, namely the latest measurement made by Fermilab of the anomalous magnetic moment of the muon $g-2$, and additionally, the fit to semi-leptonic $B$ meson decays made by different flavour groups, dominated mainly by the LHCb 2020 data. We obtain that the model can explain the former at the $1σ$ level by means of contributions coming from charged $W^{+}$ bosons interacting with exotic Majorana neutrinos at one-loop level, with the $Z'$ boson contribution itself coming from the $U(1)_X$ symmetry being negligible. However, we find that the model is able to accommodate the $b\to s\ell^{+}\ell^{-}$ transitions associated to the $B$ meson anomalies only at the $2σ$ level via tree-level $Z'$ boson exchange, while simultaneously respecting various constraints from the recent $R_{K^{(*)}}$ measurements made by the LHCb, neutrino trident production and $B-\bar B$ oscillations.

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arXiv2018

Mass problem in the Standard Model

We propose a new $\mathrm{SU}(3)_C \otimes \mathrm{SU}(2)_{L}\otimes \mathrm{U}(1)_{Y}\otimes \mathrm{U}(1)_{X}$ gauge model which is non universal respect to the three fermion families of the Standard Model. We introduce additional one top-like quark, two bottom-like quarks and three right handed neutrinos in order to have an anomaly free theory. We also consider additional three right handed neutrinos which are singlets respect to the gauge symmetry of the model to implement see saw mechanism and give masses to the light neutrinos according to the neutrino oscillation phenomenology. In the context of this horizontal gauge symmetry we find mass ansatz for leptons and quarks. In particular, from the analysis of solar, atmospheric, reactor and accelerator neutrino oscillation experiments, we get the allow region for the Yukawa couplings for the charge and neutral lepton sectors according with the mass squared differences and mixing angles for the two neutrino hierarchy schemes, normal and inverted.

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arXiv2017

A new U(1) model anomaly free for three families to address fermion mass hierarchy and neutrino physics

A new non-universal abelian extension $\mathrm{G_{SM}}\otimes \mathrm{U(1)}_{X}$ to the Standard Model free from chiral anomalies is presented. The new $X$ charges distinguish among generations so as the fermion mass matrices get zero-textures from the fermion mass hierarchy can be obtained. Regarding to neutrino physics, the model inclues Majorana fermions which induce see-saw mechanisms to get small neutrino masses. Moreover, the suitability of the model is tested by searching for regions in the parameter space which reproduce current neutrino oscillation data.

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arXiv2017

A U(1) non-universal anomaly-free model with three Higgs doublets and one singlet scalar field

The flavor problem, neutrino physics and the fermion mass hierarchy are important motivations to extend the Standard Model into the TeV scale. A new family non-universal extension is presented with three Higgs doublets, one Higgs singlet and one scalar dark matter candidate. Exotic fermions are included in order to cancel chiral anomalies and to allow family non-universal $\mathrm{U(1)}_{X}$ charges. By implementing an additional $\mathbb{Z}_{2}$ symmetry the Yukawa coupling terms are suited in such a way that the fermion mass hierarchy is obtained without fine-tuning. The neutrino sector include Majorana fermions to implement inverse see-saw mechanism. The effective mass matrix for SM neutrinos is fitted to current neutrino oscillation data to check the consistency of the model with experimental evidence, obtaining that the normal-ordering scheme is preferred over the inverse ones and the values of the neutrino Yukawa coupling constants are shown. Finally, the $h\rightarrow τμ$ lepton-flavor-violation process is addressed with the rotation matrices of the CP-even scalars, left- and right-handed charged leptons, yielding definite regions where the model is consistent with CMS reports of $\mathrm{BR}(h\rightarrow τμ)$. Keywords: Flavor Problem, Neutrino Physics, Extended Scalar Sectors, Beyond Standard Model, Fermion masses, Inverse See-Saw Mechanism, LFV.

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arXiv2017

Neutrino and CP-even Higgs boson masses in a nonuniversal $\mathrm{U}(1)'$ extension

We propose a new anomaly-free and family nonuniversal $\mathrm{U}(1)'$ extension of the standard model with the addition of two scalar singlets and a new scalar doublet. The quark sector is extended by adding three exotic quark singlets, while the lepton sector includes two exotic charged lepton singlets, three right-handed neutrinos and three sterile Majorana leptons to obtain the fermionic mass spectrum of the standard model. The lepton sector also reproduces the elements of the PMNS matrix and the squared-mass differences data from neutrino oscillation experiments. Also, analytical relations of the PMNS matrix are derived via the inverse see-saw mechanism, and numerical predictions of the parameters in both normal and inverse order scheme for the mass of the phenomenological neutrinos are obtained. We employed a simple seesaw-like method to obtain analytical mass eigenstates of the CP-even $3\times 3$ mass matrix of the scalar sector.

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arXiv2016

Diphoton decay for a 750 GeV scalar boson in a $SU(6)\otimes U(1)_{X}$ model

We propose a new $SU(6)\otimes U(1)_{X}$ GUT model free from anomalies, with a 750 GeV scalar candidate which can decay into two photons, compatible with the recent diphoton signal reported by ATLAS and CMS collaborations. This model gives masses to all fermions and may explain the 750GeV signal through one loop decays to $γγ$ with charged vector and charged Higgs bosons, as well as up- and electron-like exotic particles that arise naturally from the condition of cancellation of anomalies of the $SU(6)\otimes U(1)_{X}$ group. We obtain, for different width approximations, allowed mass regions from 900 GeV to 3 TeV for the exotic up-like quark, in agreement with ATLAS and CMS collaborations data.

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