Dias, A. G., Leite, J., Sanchez-Vega, B. L., & Vieira, W. C. (2020). Dynamical symmetry breaking and fermion mass hierarchy in the scale-invariant 3-3-1 model. Phys. Rev. D, 102(1), 015021–18pp.
Abstract: We propose an extension of the Standard Model (SM) based on the SU(3)(C) circle times SU(3)(L) circle times U(1)(X) (3-3-1) gauge symmetry and scale invariance. Maintaining the main features of the so-called 3-3-1 models, such as the cancellation of gauge anomalies related to the number of chiral fermion generations, this model exhibits a very compact scalar sector. Only two scalar triplets and one singlet are necessary and sufficient to break the symmetries dynamically via the Coleman-Weinberg mechanism. With the introduction of an Abelian discrete symmetry and assuming a natural hierarchy among the vacuum expectation values of the neutral scalar fields, we show that all particles in the model can get phenomenologically consistent masses. In particular, most of the standard fermion masses are generated via a seesaw mechanism involving some extra heavy fermions introduced for consistency. This mechanism provides a partial solution for the fermion mass hierarchy problem in the SM. Furthermore, the simplicity of the scalar sector allows us to analytically find the conditions for the potential stability up to one-loop level and show how they can be easily satisfied. Some of the new particles, such as the scalars H, H-+/- and all the non-SMvector bosons, are predicted to get masses around the TeV scale and, therefore, could be produced at the high-luminosity LHC. Finally, we show that the model features a residual symmetry, which leads to the stability of a heavy neutral particle; the latter is expected to show up in experiments as missing energy.
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de Anda, F. J., Valle, J. W. F., & Vaquera-Araujo, C. A. (2020). Flavour and CP predictions from orbifold compactification. Phys. Lett. B, 801, 135195–9pp.
Abstract: 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 delta(l) similar or equal to+268 degrees. The effective neutrinoless double-beta decay mass parameter is also sharply predicted as < m(beta beta)> similar or equal to 2.65 meV.
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Arbelaez, C., Carcamo Hernandez, A. E., Cepedello, R., Kovalenko, S., & Schmidt, I. (2020). Sequentially loop suppressed fermion masses from a single discrete symmetry. J. High Energy Phys., 06(6), 043–24pp.
Abstract: We propose a systematic and renormalizable sequential loop suppression mechanism to generate the hierarchy of the Standard Model fermion masses from one discrete symmetry. The discrete symmetry is sequentially softly broken in order to generate one-loop level masses for the bottom, charm, tau and muon leptons and two-loop level masses for the lightest Standard Model charged fermions. The tiny masses for the light active neutrinos are produced from radiative type-I seesaw mechanism, where the Dirac mass terms are effectively generated at two-loop level.
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Escribano, P., Hirsch, M., Nava, J., & Vicente, A. (2022). Observable flavor violation from spontaneous lepton number breaking. J. High Energy Phys., 01(1), 098–31pp.
Abstract: We propose a simple model of spontaneous lepton number violation with potentially large flavor violating decays, including the possibility that majoron emitting decays, such as μ-> e J, saturate the experimental bounds. In this model the majoron is a singlet-doublet admixture. It generates a type-I seesaw for neutrino masses and contains also a vector-like lepton. As a by-product, the model can explain the anomalous (g – 2)(mu), in parts of its parameter space, where one expects that the branching ratio of the Higgs to muons is changed with respect to Standard Model expectations. However, the explanation of the muon g – 2 anomaly would lead to tension with recent astrophysical bounds on the majoron coupling to muons.
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Leite, J., Morales, A., Valle, J. W. F., & Vaquera-Araujo, C. A. (2020). Scotogenic dark matter and Dirac neutrinos from unbroken gauged B – L symmetry. Phys. Lett. B, 807, 135537–5pp.
Abstract: We propose a simple extension of the standard model where neutrinos get naturally small “scotogenic” Dirac masses from an unbroken gauged B – L symmetry, ensuring dark matter stability. The associated gauge boson gets mass through the Stueckelberg mechanism. Two scenarios are identified, and the resulting phenomenology briefly sketched.
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Chen, P., Ding, G. J., Lu, J. N., & Valle, J. W. F. (2020). Predictions from warped flavor dynamics based on the T ' family group. Phys. Rev. D, 102(9), 095014–17pp.
Abstract: We propose a realistic theory of fermion masses and mixings using a five-dimensional warped scenario where all fermions propagate in the bulk and the Higgs field is localized on the IR bran. The assumed T' flavor symmetry is broken on the branes by flavon fields, providing a consistent scenario where fermion mass hierarchies arise from adequate choices of the bulk mass parameters, while quark and lepton mixing angles are restricted by the family symmetry. Neutrino mass splittings, mixing parameters and the Dirac CP phase all arise from the type-I seesaw mechanism and are tightly correlated, leading to predictions for the neutrino oscillation parameters, as well as expected 0 nu beta beta decay rates within reach of upcoming experiments. The scheme also provides a good global description of flavor observables in the quark sector.
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Amerio, A., Calore, F., Serpico, P. D., & Zaldivar, B. (2024). Deepening gamma-ray point-source catalogues with sub-threshold information. J. Cosmol. Astropart. Phys., 03(3), 055–18pp.
Abstract: We propose a novel statistical method to extend Fermi-LAT catalogues of highlatitude -y-ray sources below their nominal threshold. To do so, we rely on the determination of the differential source -count distribution of sub -threshold sources which only provides the statistical flux distribution of faint sources. By simulating ensembles of synthetic skies, we assess quantitatively the likelihood for pixels in the sky with relatively low -test statistics to be due to sources, therefore complementing the source -count distribution with spatial information. Besides being useful to orient efforts towards multi -messenger and multi -wavelength identification of new -y-ray sources, we expect the results to be especially advantageous for statistical applications such as cross -correlation analyses.
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Câmara, H. B., Joaquim, F. R., & Valle, J. W. F. (2023). Dark-sector seeded solution to the strong CP problem. Phys. Rev. D, 108(9), 095003–6pp.
Abstract: We propose a novel realization of the Nelson-Barr mechanism “seeded” by a dark sector containing scalars and vectorlike quarks. Charge parity (CP) and a Z8 symmetry are spontaneously broken by the complex vacuum expectation value of a singlet scalar, leaving a residual Z2 symmetry that stabilizes dark matter (DM). A complex Cabibbo-Kobayashi-Maskawa matrix arises via one-loop corrections to the quark mass matrix mediated by the dark sector. In contrast with other proposals where nonzero contributions to the strong CP phase arise at the one-loop level, in our case this occurs only at two loops, enhancing naturalness. Our scenario also provides a viable weakly interacting massive particle scalar DM candidate.
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Aja, B. et al, & Gimeno, B. (2022). The Canfranc Axion Detection Experiment (CADEx): search for axions at 90 GHz with Kinetic Inductance Detectors. J. Cosmol. Astropart. Phys., 11(11), 044–29pp.
Abstract: We propose a novel experiment, the Canfranc Axion Detection Experiment (CADEx), to probe dark matter axions with masses in the range 330-460 μeV, within the W-band (80-110 GHz), an unexplored parameter space in the well-motivated dark matter window of Quantum ChromoDynamics (QCD) axions. The experimental design consists of a microwave resonant cavity haloscope in a high static magnetic field coupled to a highly sensitive detecting system based on Kinetic Inductance Detectors via optimized quasi-optics (horns and mirrors). The experiment is in preparation and will be installed in the dilution refrigerator of the Canfranc Underground Laboratory. Sensitivity forecasts for axion detection with CADEx, together with the potential of the experiment to search for dark photons, are presented.
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Angles-Castillo, A., Perez, A., & Roldan, E. (2024). Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum. New J. Phys., 26(2), 023004–16pp.
Abstract: We propose a nonlinear quantum walk model inspired in a photonic implementation in which the polarization state of the light field plays the role of the coin-qubit. In particular, we take profit of the nonlinear polarization rotation occurring in optical media with Kerr nonlinearity, which allows to implement a nonlinear coin operator, one that depends on the state of the coin-qubit. We consider the space-time continuum limit of the evolution equation, which takes the form of a nonlinear Dirac equation. The analysis of this continuum limit allows us to gain some insight into the existence of different solitonic structures, such as bright and dark solitons. We illustrate several properties of these solitons with numerical calculations, including the effect on them of an additional phase simulating an external electric field.
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