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R. Martinez

Publications and source records attributed to R. Martinez.

At least 37 records · Page 2Linked to original sources
arXiv2019

A $U(1)_{X}$ extension to the SM with three families and Peccei Quinn symmetry

We propose a non-universal $U(1)_{X}$ extension to the Standard Model with three families and an additional global anomala Peccei-Quinn (PQ) symmetry. The breaking of the former allows us to give masses to the exotic fermionic sector and the later generates the necessary zeros in the mass matrices to explain the fermionic mass hierarchy. In addition, the large energy scale associated with the spontaneously breaking (SSB) of the PQ symmetry provides a solution to the strong CP-problem and an axion that could be a possible dark matter candidate. Also, the SSB allows to generate right-handed neutrino masses, so the active neutrinos acquire $eV$-mass values due to the see-saw mechanism implementation.

hep-ph↗
arXiv2019

A $U(1)_X$ extension to the MSSM with three families

We propose a supersymmetric extension of the anomaly-free and three families nonuniversal $U(1)$ model, with the inclusion of four Higgs doublets and four Higgs singlets. 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 neutrinos to obtain the fermionic mass spectrum. 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 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. The electron and up, down and strange quarks are massless at tree level, but they get masses through radiative correction at one loop level coming from the sleptons and Higgsinos contributions. We show that the model predicts a like-Higgs SM mass at electroweak scale by using the VEV according to the symmetry breaking and fermion masses.

hep-ph↗
arXiv2019

A non-universal $U(1)_{X}$ gauge extension to the MSSM

We propose a supersymmetric extension of the anomaly-free and three families nonuniversal $U(1)$ model, with the inclusion of four Higgs doublets and four Higgs singlets. 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 neutrinos to obtain the fermionic mass spectrum. 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 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. The electron and up, down and strange quarks are massless at tree level, but they get masses through radiative correction at one loop level coming from the sleptons and Higgsinos contributions. We show that the model predicts a like-Higgs SM mass at electroweak scale by using the VEV according to the symmetry breaking and fermion masses.

hep-ph↗
arXiv2019

The meteorite flux of the last 2 Myr recorded in the Atacama desert

The evolution of the meteorite flux to the Earth can be studied by determining the terrestrial ages of meteorite collected in hot deserts. We have measured the terrestrial ages of 54 stony meteorites from the El Médano area, in the Atacama Desert, using the cosmogenic nuclide chlorine 36. With an average age of 710 ka, this collection is the oldest collection of non fossil meteorites at the Earth's surface. This allows both determining the average meteorite flux intensity over the last 2 Myr (222 meteorites larger than 10 g per km2 per Myr) and discussing its possible compositional variability over the Quaternary period. A change in the flux composition, with more abundant H chondrites, occurred between 0.5 and 1 Ma, possibly due to the direct delivery to Earth of a meteoroid swarm from the asteroid belt.

astro-ph.EP↗
arXiv2019

CP symmetry violation in the scalar sector of 331 models

In order to understand some frameworks for CP Violation scenarios in the scalar sector, a 331 model was considered which its main property is the incorporation of a local group symmetry SU(3) in the electroweak sector. In particular, a 331 model with a particular choice of free parameter. CP Violation scenarios were obtained by introducing a discrete symmetry in the scalar triplets, which exhibit a spontaneous CP Violation frame with just one independent CP phase associated. Mass state rotations were obtained.

hep-ph↗
arXiv2018

See saw mechanism with Yukawa alignment for neutrinos

In the extension of the standard model with one right-handed neutrino and one Higgs triplet, we propose a suppression mechanism, obtaining small masses for the active neutrinos, while mixing angles are predicted with a right-handed neutrino at the TeV scale and Yukawa couplings at the order of $\mathcal{O}(1)$. In this extension, the seesaw formula is proportional to the difference between two Yukawa couplings: the one that governs the interactions of the ordinary matter through the Higgs triplet, and the coupling of the new neutrino through the scalar doublet, so that by aligning both Yukawa couplings, exact zero-mass active neutrinos are obtained. By perturbating this alignment condition, we obtain neutrino masses proportional to the magnitude and direction of the perturbation in the flavour space. Bimaximal and nearly bimaximal mass structures emerge from specific unalignment forms.

hep-ph↗
arXiv2018

Beyond $\mathcal{R}(D^{(*)})$ with the general 2HDM-III for $b\to cτν$

We review the parameter regions allowed by measurements of $\mathcal{R}(D^{(*)})$ and by a theoretical limit on ${\cal B}(B_{c}\toτν)$ in terms of generic scalar and pseudoscalar new physics couplings, $g_s$ and $g_p$. We then use these regions as constraints to predict the ranges for additional observables in $b\to cτν$ including the differential decay distributions $dΓ/dq^{2}$; the ratios $\mathcal{R}(J/ψ)$ and $\mathcal{R}(Λ_{c})$; and the tau-lepton polarisation in $B\to D^{(\star)}τν$, with emphasis on the CP violating normal polarisation. Finally we map the allowed regions in $g_s$ and $g_p$ into the parameters of four versions of the Yukawa couplings of the general 2HDM-III model. We find that the model is still viable but could be ruled out by a confirmation of a large $\mathcal{R}(J/ψ)$.

hep-ph↗
arXiv2018

B meson decay anomaly with a non-universal U(1)' extension

We propose an extension of the standard model with an extra U(1)' abelian symmetry, three Higgs doublets and one Higgs singlet, where the new U(1)' charges are flavour non-universal. As a result, the model introduces an enlarger particle spectrum in the TeV scale with large new physics possibilities. The model reproduces the mixing angles and mass structures of the quarks, charged and neutral leptons. We found that the observed anomaly of the $B^{+}\rightarrow K^+ \ell \ell$ decay can be explained due to the existence of couplings with new extra fermions at the TeV scale.

hep-ph↗
arXiv2018

Fermion mass hierarchy from nonuniversal abelian extensions of the Standard Model

A nonuniversal abelian extension $\mathrm{U(1)}_{X}$ free from chiral anomalies is introduced into the Standard Model (SM), in order to evaluate its suitability in addressing the fermion mass hierarchy (FMH) by using seesaw mechanisms (SSM). In order to break the electroweak symmetry, three Higgs doublets are introduced, which give mass at tree-level to the top and bottom quarks, and the muon lepton. With an electroweak singlet scalar field, the $U(1)_{X}$ symmetry is broken and the exotic particles acquire masses. The light particles in the SM obtain their masses via SSM and Yukawa couplings differences. Active neutrino masses are generated through inverse seesaw mechanisms (ISM). Additionally, the algebraic expressions for the mixing angles for quarks and leptons are also shown in the article. Keywords: Flavor Problem, Neutrino Physics, Extended Scalar Sectors, Beyond Standard Model, Fermion masses, Inverse seesaw Mechanism.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
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.

hep-ph↗
arXiv2017

On the Horava-Lifshitz-like Gross-Neveu model

We describe a Horava-Lifshitz-like reformulated four-fermion Gross-Neveu model describing the dynamics of two-component spinors in (2+1)-dimensional space-time. Within our study, we introduce the Lagrange multiplier, study the gap equation (including the finite temperature case) which turns out to display essentially distinct behaviors for even and odd values of the critical exponent z, and show that the dynamical parity breaking occurs only for the odd z. We demonstrate that for any odd z, there exists a critical temperature at which the dynamical parity breaking disappears. Besides of this, we obtain the effective propagator and show that the resulting effective theory is renormalizable within the framework of the 1/N expansion for all values of z. As one more application of the dynamical parity breaking, we consider coupling of the vector field to the fermions in the case of a simplified spinor-vector coupling and discuss the generation the Chern-Simons term.

hep-th↗
arXiv2016

The right top coupling in the aligned two-Higgs-doublet model

We compute the right top quark coupling in the aligned two-Higgs-doublet model. In the Standard Model the real part of this coupling is dominated by QCD-gluon-exchange diagram, but the imaginary part, instead, is purely electroweak at one loop. Within this model we show that values for the imaginary part of the coupling up to one order of magnitude larger than the electroweak prediction can be obtained. For the real part of the electroweak contribution we find that it can be up to three orders of magnitude larger than the standard model one. We also present detailed results of the one loop analytical computation.

hep-ph↗
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.

hep-ph↗
arXiv2016

Diphoton decay for a $750$ GeV scalar boson in an $U(1)_{X}$ model

In the context of a nonuniversal and anomaly free $U(1)_{X}$ extension of the standard model, we examine the decay of a $750$GeV scalar singlet state, $ξ_χ$, as a possible explanation of the observed diphoton excess announced by the ATLAS and CMS collaborations at CERN-LHC collider. One-loop decay to photons is allowed through three heavy singlet quarks and one charged Higgs boson into the loop. We obtain, for different width approximations and for masses of the exotic singlet quarks in the region $[900,\,3000]$ GeV, a production cross section $σ(pp\toξ_χ\toγγ)$ compatible with ATLAS and CMS collaborations data. We also include another scalar singlet, $σ$, as a dark matter candidate that may couple with the 750 GeV scalar at tree level with production cross sections in agreement with ATLAS and CMS.

hep-ph↗
arXiv2016

$\boldsymbol{SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}}$ models in view of the $750$ GeV diphoton signal

We analyze the recent diphoton signal reported by ATLAS and CMS collaborations in the context of the $SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}$ anomaly free models, with a 750 GeV scalar candidate which can decay into two photons. These models may explain the 750GeV signal by means of one loop decays to $γγ$ through charged vector and Higgs bosons, as well as top-, bottom- and electron-like exotic particles that arise naturally from the condition of anomaly cancellations of the $SU(3)_{C}\otimes SU(3)_{L}\otimes U(1)_{X}$ models.

hep-ph↗