arXiv subjects

José W. F. Valle

Publications and source records attributed to José W. F. Valle.

At least 55 records · Page 3Linked to original sources

arXiv2020

Probing new neutral gauge bosons with CEvNS and neutrino-electron scattering

The potential for probing extra neutral gauge boson mediators ($Z^\prime$) from low-energy measurements is comprehensively explored. Our study mainly focuses on $Z^\prime$ mediators present in string-inspired $E_6$ models and left-right symmetry. We estimate the sensitivities of coherent-elastic neutrino-nucleus scattering (CE$ν$NS) and neutrino-electron scattering experiments. Our results indicate that such low-energy high-intensity measurements can provide a valuable probe, complementary to high-energy collider searches and electroweak precision measurements.

hep-ph↗

arXiv2020

A theory for scotogenic dark matter stabilised by residual gauge symmetry

Dark matter stability can result from a residual matter-parity symmetry, following naturally from the spontaneous breaking of the gauge symmetry. Here we explore this idea in the context of the $\mathrm{SU(3)_c \otimes SU(3)_L \otimes U(1)_X \otimes U(1)_{N}}$ electroweak extension of the standard model. The key feature of our new scotogenic dark matter theory is the use of a triplet scalar boson with anti-symmetric Yukawa couplings. This naturally implies that one of the light neutrinos is massless and, as a result, there is a lower bound for the $\rm 0νββ$ decay rate.

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arXiv2020

Neutrino physics outlook

Here I identify some of the opportunities in particle physics associated to the lepton sector, according to their perceived significance, and taking into account the current state-of-the-art.

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arXiv2020

Flavour and CP predictions from orbifold compactification

We propose a theory for fermion masses and mixings in which an $A_4$ family symmetry arises naturally from a six-dimensional spacetime after orbifold compactification. The flavour symmetry leads to the successful "golden" quark-lepton unification formula. The model reproduces oscillation parameters with good precision, giving sharp predictions for the CP violating phases of quarks and leptons, in particular $δ^\ell \simeq +268 ^\circ$. The effective neutrinoless double-beta decay mass parameter is also sharply predicted as $\langle m_{ββ}\rangle \simeq 2.65\ meV$.

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arXiv2019

Scotogenic dark matter stability from gauged matter parity

We explore the idea that dark matter stability results from the presence of a matter-parity symmetry, arising naturally as a consequence of the spontaneous breaking of an extended $\mathrm{SU(3) \otimes SU(3)_L \otimes U(1)_X \otimes U(1)_{N}}$ electroweak gauge symmetry with fully gauged B-L. Using this framework we construct a theory for scotogenic dark matter and analyze its main features.

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arXiv2019

Light majoron cold dark matter from topological defects and the formation of boson stars

We show that for a relatively light majoron ($\ll 100 $ eV) non-thermal production from topological defects is an efficient production mechanism. Taking the type I seesaw as benchmark scheme, we estimate the primordial majoron abundance and determine the required parameter choices where it can account for the observed cosmological dark matter. The latter is consistent with the scale of unification. Possible direct detection of light majorons with future experiments such as PTOLEMY and the formation of boson stars from the majoron dark matter are also discussed.

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arXiv2019

Status and prospects of `bi-large' leptonic mixing

Bi-large patterns for the leptonic mixing matrix are confronted with current neutrino oscillation data. We analyse the status of these patterns and determine, through realistic simulations, the potential of upcoming long-baseline experiment DUNE in testing bi-large \emph{ansatze} and discriminating amongst them.

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arXiv2019

CP Symmetries as Guiding Posts: revamping tri-bi-maximal Mixing. Part II

In this follow up of arXiv:1812.04663 we analyze the generalized CP symmetries of the charged lepton mass matrix compatible with the complex version of the Tri-Bi-Maximal (TBM) lepton mixing pattern. These symmetries are used to `revamp' the simplest TBM \textit{Ansatz} in a systematic way. Our generalized patterns share some of the attractive features of the original TBM matrix and are consistent with current oscillation experiments. We also discuss their phenomenological implications both for upcoming neutrino oscillation and neutrinoless double beta decay experiments.

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arXiv2019

Neutrino predictions from a left-right symmetric flavored extension of the standard model

We propose a left-right symmetric electroweak extension of the Standard Model based on the $Δ\left( 27\right)$ family symmetry. The masses of all electrically charged Standard Model fermions lighter than the top quark are induced by a Universal Seesaw mechanism mediated by exotic fermions. The top quark is the only Standard Model fermion to get mass directly from a tree level renormalizable Yukawa interaction, while neutrinos are unique in that they get calculable radiative masses through a low-scale seesaw mechanism. The scheme has generalized $μ-τ$ symmetry and leads to a restricted range of neutrino oscillations parameters, with a nonzero neutrinoless double beta decay amplitude lying at the upper ranges generically associated to normal and inverted neutrino mass ordering.

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arXiv2019

Spontaneous Breaking of Lepton Number and Cosmological Domain Wall Problem

We show that if global lepton number symmetry is spontaneously broken in a post inflation epoch, then it can lead to the formation of cosmological domain walls. This happens in the well-known "Majoron paradigm" for neutrino mass generation. We propose some realistic examples which allow spontaneous lepton number breaking to be safe from such domain walls.

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arXiv2019

Testing generalized CP symmetries with precision studies at DUNE

We examine the capabilities of the DUNE experiment in probing leptonic CP violation within the framework of theories with generalized CP symmetries characterized by the texture zeros of the corresponding CP transformation matrices. We investigate DUNE's potential to probe the two least known oscillation parameters, the atmospheric mixing angle $θ_{23}$ and the Dirac CP-phase $δ_{\rm CP}$. We fix theory-motivated benchmarks for ($ \sin^2θ_{23}, δ_{\rm CP} $) and take them as true values in our simulations. Assuming 3.5 years of neutrino running plus 3.5 years in the antineutrino mode, we show that in all cases DUNE can significantly constrain and in certain cases rule out the generalized CP texture zero patterns.

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arXiv2019

Predicting neutrino oscillations with "bi-large" lepton mixing matrices

We propose two schemes for the lepton mixing matrix $U = U_l^\dagger U_ν$, where $U = U_l$ refers to the charged sector, and $U_ν$ denotes the neutrino diagonalization matrix. We assume $U_ν$ to be CP conserving and its three angles to be connected with the Cabibbo angle in a simple manner. CP violation arises solely from the $U_l$, assumed to have the CKM form, $U_l\simeq V_{\rm CKM}$, suggested by unification. Oscillation parameters depend on a single parameter, leading to narrow ranges for the "solar" and "accelerator" angles $θ_{12}$ and $θ_{23}$, as well as for the CP phase, predicted as $δ_{\rm CP}\sim 1.3π$.

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arXiv2018

Simplest Scoto-Seesaw Mechanism

By combining the simplest (3,1) version of the seesaw mechanism containing a single heavy "right-handed" neutrino with the minimal scotogenic approach to dark matter, we propose a theory for neutrino oscillations. The "atmospheric" mass scale arises at tree level from the seesaw, while the "solar" oscillation scale emerges radiatively, through a loop involving the "dark sector" exchange. Such simple setup gives a clear interpretation of the neutrino oscillation lengths, has a viable WIMP dark matter candidate, and implies a lower bound on the neutrinoless double beta decay rate.

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arXiv2018

Decaying warm dark matter and structure formation

We examine the cosmology of warm dark matter (WDM), both stable and decaying, from the point of view of structure formation. We compare the matter power spectrum associated to WDM masses of 1.5 keV and 0.158 keV, with that expected for the stable cold dark matter $Λ$CDM$\equiv$SCDM paradigm, taken as our reference model. We scrutinize the effects associated to the warm nature of dark matter, as well as the fact that it decays. The decaying warm dark matter (DWDM) scenario is well-motivated, emerging in a broad class of particle physics theories where neutrino masses arise from the spontaneous breaking of a continuous global lepton number symmetry. The majoron arises as a Nambu-Goldstone boson, and picks up a mass from gravitational effects, that explicitly violate global symmetries. The majoron necessarily decays to neutrinos, with an amplitude proportional to their tiny mass, which typically gives it cosmologically long lifetimes. Using N-body simulations we show that our DWDM picture leads to a viable alternative to the $Λ$CDM scenario, with predictions that can differ substantially on small scales.

astro-ph.CO↗

arXiv2018

CP Symmetries as Guiding Posts: Revamping Tri-Bi-Maximal Mixing-I

We analyze the possible generalized CP symmetries admitted by the Tri-Bi-Maximal (TBM) neutrino mixing. Taking advantage of these symmetries we construct in a systematic way other variants of the standard TBM ansatz. Depending on the type and number of generalized CP symmetries imposed, we get new mixing matrices, all of which related to the original TBM matrix. One of such "revamped" TBM variants is the recently discussed mixing matrix of arXiv:1806.03367. We also briefly discuss the phenomenological implications following from these mixing patterns.

hep-ph↗

arXiv2018

SO(3) family symmetry and axions

Motivated by the idea of comprehensive unification, we study a gauged SO(3) flavor extension of the extended Standard Model, including right-handed neutrinos and a Peccei-Quinn symmetry with simple charge assignments. The model accommodates the observed fermion masses and mixings and yields a characteristic, successful relation among them. The Peccei-Quinn symmetry is an essential ingredient.

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arXiv2018

Neutrino Predictions from Generalized CP Symmetries of Charged Leptons

We study the implications of generalized CP transformations acting on the mass matrices of charged leptons in a model-independent way. Generalized $e-μ$, $e-τ$ and $μ-τ$ symmetries are considered in detail. In all cases the physical parameters of the lepton mixing matrix, three mixing angles and three CP phases can be expressed in terms of a restricted set of independent "theory" parameters that characterize a given choice of CP transformation. This leads to implications for neutrino oscillations as well as neutrinoless double beta decay experiments.

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arXiv2018

Realistic Tri-Bi-Maximal neutrino mixing

We propose a generalized version of the Tri-Bi-Maximal (TBM) ansatz for lepton mixing, leading to non-zero reactor angle $θ_{13}$ and CP violation. The latter is characterized by two CP phases. The Dirac phase affecting neutrino oscillations is nearly maximal ($δ_{CP} \sim \pm π/2$), while the Majorana phase implies narrow allowed ranges for the neutrinoless double beta decay amplitude. The solar angle $θ_{12}$ lies nearly at its TBM value, while the atmospheric angle $θ_{23}$ has the TBM value for maximal $δ_{CP}$. Neutrino oscillation predictions can be tested in present and upcoming experiments.

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