arXiv subjects

Eduardo Peinado

Publications and source records attributed to Eduardo Peinado.

At least 37 records · Page 2Linked to original sources

arXiv2021

Flavored axion in the UV-complete Froggatt-Nielsen models

We propose UV-completions of Froggatt-Nielsen-Peccei-Quinn models of fermion masses and mixings with flavored axions, by incorporating heavy fields. Here, the $U(1)$ Froggatt-Nielsen symmetry is identified with the Peccei-Quinn symmetry to solve the strong CP problem along with the mass hierarchies of the Standard Model fermions. We take into account leading order contributions to the fermion mass matrices giving rise to Nearest-Neighbour-Interaction structure in the quark sector and $A_2$ texture in the neutrino sector. A comprehensive numerical analysis has been performed for the fermion mass matrices. Subsequently, we investigate the resulting axion flavor violating couplings and the axion-photon coupling arising from the model.

hep-ph↗

arXiv2021

Physics reach of a low threshold scintillating argon bubble chamber in coherent elastic neutrino-nucleus scattering reactor experiments

The physics reach of a low threshold (100 eV) scintillating argon bubble chamber sensitive to Coherent Elastic neutrino-Nucleus Scattering (CE$ν$NS) from reactor neutrinos is studied. The sensitivity to the weak mixing angle, neutrino magnetic moment, and a light $Z'$ gauge boson mediator are analyzed. A Monte Carlo simulation of the backgrounds is performed to assess their contribution to the signal. The analysis shows that world-leading sensitivities are achieved with a one-year exposure for a 10 kg chamber at 3 m from a 1 MW$_{th}$ research reactor or a 100 kg chamber at 30 m from a 2000 MW$_{th}$ power reactor. Such a detector has the potential to become the leading technology to study CE$ν$NS using nuclear reactors.

hep-ex↗

arXiv2020

Neutrino phenomenology in a left-right $D_4$ symmetric model

We present a minimal left-right symmetric flavor model and analyze the predictions for the neutrino sector. In this scenario, the Yukawa sector is shaped by the dihedral $D_4$ symmetry which leads to correlations for the neutrino mixing parameters. We end up with four possible solutions within this model. We further analyzed the impact of the upcoming long-baseline neutrino oscillation experiment DUNE. Due to its high sensitivity, DUNE will be able to rule out two of the solutions. Finally, the prediction for the neutrinoless double beta decay for the model has also been examined.

hep-ph↗

arXiv2020

Fermion Dark Matter and Radiative Neutrino Masses from Spontaneous Lepton Number Breaking

In this paper, we study the viability of having a fermion Dark Matter particle below the TeV mass scale in connection to the neutrino mass generation mechanism. The simplest realization is achieved within the scotogenic model where neutrino masses are generated at the 1-loop level. Hence, we consider the case where the dark matter particle is the lightest $\mathbb{Z}_2$-odd Majorana fermion running in the neutrino mass loop. We assume that lepton number is broken dynamically due to a lepton number carrier scalar singlet which acquires a non-zero vacuum expectation value. In the present scenario the Dark Matter particles can annihilate via $t$- and $s$-channels. The latter arises from the mixing between the new scalar singlet and the Higgs doublet. We identify three different Dark Matter mass regions below 1 TeV that can account for the right amount of dark matter abundance in agreement with current experimental constraints. We compute the Dark Matter-nucleon spin-independent scattering cross-section and find that the model predicts spin-independent cross-sections ``naturally'' dwelling below the current limit on direct detection searches of Dark Matter particles reported by XENON1T.

hep-ph↗

arXiv2020

Dirac neutrinos from Peccei-Quinn symmetry: two examples

We aim to explain the nature of neutrinos using Peccei-Quinn symmetry. We discuss two simple scenarios, one based on a type-II Dirac seesaw and the other in a one-loop neutrino mass generation, which solve the strong CP problem and naturally lead to Dirac neutrinos. In the first setup latest neutrino mass limit gives rise to axion which is in the reach of conventional searches. Moreover, we have both axion as well as WIMP dark mater for our second set up.

hep-ph↗

arXiv2020

Dark matter stability and Dirac neutrinos using only Standard Model symmetries

We provide a generic framework to obtain stable dark matter along with naturally small Dirac neutrino masses generated at the loop level. This is achieved through the spontaneous breaking of the global $U(1)_{B-L}$ symmetry already present in Standard Model. The $U(1)_{B-L}$ symmetry is broken down to a residual even $\mathcal{Z}_n$; $n \geq 4$ subgroup. The residual $\mathcal{Z}_n$ symmetry simultaneously guarantees dark matter stability and protects the Dirac nature of neutrinos. The $U(1)_{B-L}$ symmetry in our setup is anomaly free and can also be gauged in a straightforward way. Finally, we present an explicit example using our framework to show the idea in action.

hep-ph↗

arXiv2019

Systematic classification of two loop d = 4 Dirac neutrino mass models and the Diracness-dark matter stability connection

We provide a complete systematic classification of all two-loop realizations of the dimension four operator for Dirac neutrino masses. Our classification is multi-layered, starting first with a classification in terms of all possible distinct two-loop topologies. Then we discuss the possible diagrams for each topology. Model-diagrams originating from each diagram are then considered. The criterion for genuineness is also defined and discussed at length. Finally, as examples, we construct two explicit models which also serve to highlight the intimate connection between the Dirac nature of neutrinos and dark matter stability.

hep-ph↗

arXiv2019

Dirac neutrinos from Peccei-Quinn symmetry: a fresh look at the axion

We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a type I Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.

hep-ph↗

arXiv2019

Dynamical generation of neutrino mass scales

In this letter we present a simple scenario where the mass scales associated to atmospheric and solar neutrino oscillations are obtained through the dynamical generation of neutrino masses. The main idea is that the two different scales are the result of two independent mechanisms, namely a type-I seesaw generating the atmospheric scale and a radiative 1-loop process providing the solar one. A relation of the two scales, reminiscent of the so-called sequential dominance, is thus obtained.

hep-ph↗

arXiv2019

The role of residual symmetries in dark matter stability and the neutrino nature

We consider the class of models where Dirac neutrino masses at one loop and the dark matter stability can be obtained using only the global $U(1)_{B-L}$ symmetry already present in Standard Model. We discuss how the residual $\mathcal{Z}_n$ subgroup, left unbroken after the breaking of $U(1)_{B-L}$, dictates the neutrino nature, namely if they are Dirac or Majorana particles, as well as determines the stability of the dark matter candidate in such models. In particular, we show that without the correct breaking of $U(1)_{B-L}$ to an appropriate residual $\mathcal{Z}_n$ symmetry, the Dirac nature of neutrinos and/or dark matter stability might be lost. For completeness we also provide some examples where the dark matter stability is accidental or lost completely. Finally, we discuss one example model where the Dirac neutrinos with naturally small one loop masses as well as dark matter stability, are both protected by the same residual $\mathcal{Z}_6$ subgroup, without need for adding any new explicit or accidental symmetries beyond the Standard Model symmetries.

hep-ph↗

arXiv2019

Scotogenic Dark Symmetry as a residual subgroup of Standard Model Symmetries

We show that the scotogenic dark symmetry can be obtained as a residual subgroup of the global $U(1)_{B-L}$ symmetry already present in Standard Model. We propose a general framework where the $U(1)_{B-L}$ symmetry is spontaneously broken to an even $\mathcal{Z}_{2n}$ subgroup, setting the general conditions for neutrinos to be Majorana and the dark matter stability in terms of the residual $\mathcal{Z}_{2n}$. Under this general framework, as examples, we build a class of simple models where, in the scotogenic spirit, the dark matter candidate is the lightest particle running inside the neutrino mass loop. The global $U(1)_{B-L}$ symmetry in our framework being anomaly free can also be gauged in a straightforward manner leading to a richer phenomenology.

hep-ph↗

arXiv2018

Neutrinophilic Dark Matter in the epoch of IceCube and Fermi-LAT

The recent observation of the blazar TXS 0506+056 suggests the presence of a hard power-law component in the extraterrestrial TeV-PeV neutrino flux, in agreement with the IceCube analysis on the 8-year through-going muon neutrinos from the Northern Sky. This is slightly in tension with the soft power-law neutrino flux deduced by the IceCube 6-year High Energy Starting Events data. A possible solution to such a puzzle is assuming a two-component neutrino flux. In this paper, we focus on the case where, in addition to an astrophysical power-law, the second component is a pure neutrino line produced by decaying Dark Matter particles. We investigate how to realize a neutrinophilic decaying Dark Matter in an extension of the Standard Model. The main features of the model are: i) the requirement of a new symmetry like a global $U(1)$ charge; ii) the Dirac nature of active neutrinos; iii) a low-reheating temperature of the Universe of about 1 TeV. We perform a likelihood statistical analysis to fit the IceCube data according to the present Fermi-LAT gamma-rays constraints.

hep-ph↗

arXiv2017

Flavour-symmetric type-II Dirac neutrino seesaw mechanism

We propose a Standard Model extension with underlying A4 flavour symmetry where small Dirac neutrino masses arise from a Type-II seesaw mechanism. The model predicts the "golden" flavour-dependent bottom-tau mass relation, requires an inverted neutrino mass ordering and non-maximal atmospheric mixing angle. Using the latest neutrino oscillation global fit we derive restrictions on the oscillation parameters, such as a correlation between Dirac CP phase and the lightest neutrino mass.

hep-ph↗

arXiv2016

Delta(54) flavor phenomenology and strings

Delta(54) can serve as a flavor symmetry in particle physics, but remains almost unexplored. We show that in a classification of semi-realistic Z3xZ3 heterotic string orbifolds, Delta(54) turns out to be the most natural flavor symmetry, providing additional motivation for its study. We revisit its phenomenological potential from a low-energy perspective and subject to the constraints of string models. We find a model with Delta(54) arising from heterotic orbifolds that leads to the Gatto-Sartori-Tonin relation for quarks and charged-leptons. Additionally, in the neutrino sector, it leads to a normal hierarchy for neutrino masses and a correlation between the reactor and the atmospheric mixing angles, the latter taking values in the second octant and being compatible at three sigmas with experimental data.

hep-ph↗

arXiv2016

Two-loop Dirac neutrino mass and WIMP dark matter

We propose a "scotogenic" mechanism relating small neutrino mass and cosmological dark matter. Neutrinos are Dirac fermions with masses arising only in two--loop order through the sector responsible for dark matter. Two triality symmetries ensure both dark matter stability and strict lepton number conservation at higher orders. A global spontaneously broken U(1) symmetry leads to a physical $Diracon$ that induces invisible Higgs decays which add up to the Higgs to dark matter mode. This enhances sensitivities to spin-independent WIMP dark matter search below $m_h/2$.

hep-ph↗

arXiv2016

A new radiative neutrino mass generation mechanism with higher dimensional scalar representations and custodial symmetry

A new realization for radiative neutrino mass generation is presented. Based on the requirement of tree-level custodial symmetry and the introduction of higher (greater than two) dimensional representations for scalar fields, a specific scenario with a scalar septet is presented that generates neutrino Majorana masses radiatively. This is accomplished through an eleven dimensional operator that requires the addition of several scalar fields and a SU(2) 5-plet of new fermions, together with a Z2 that guarantees the preservation of custodial symmetry. The phenomenology of the setup is rather rich and includes a dark matter candidate

hep-ph↗

arXiv2015

Effects of an H-mu-tau coupling in quarkonium lepton flavor violation decays

In this work we study the consistency of a possible non-vanishing coupling $Hμτ$ of the order of $3.6\times 10^{-3}$ as pointed recently by the CMS and ATLAS collaborations, with measured lepton flavor violation processes involving quarkonium. We show that the most promising channel to confirm this excess is to look for the lepton flavor tau decay into a $f_0$ and $μ$ where the experimental limit could strongly improved with the new B factories as Belle II.

hep-ph↗

arXiv2015

Relating quarks and leptons with the T7 flavour group

In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results lead to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

hep-ph↗