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Bonilla, C., & Valle, J. W. F. (2016). Naturally light neutrinos in Diracon model. Phys. Lett. B, 762, 162–165.
Abstract: We propose a simple model for Dirac neutrinos where the smallness of neutrino mass follows from a parameter kappa whose absence enhances the symmetry of the theory. Symmetry breaking is performed in a two-doublet Higgs sector supplemented by a gauge singlet scalar, realizing an accidental global U(1) symmetry. Its spontaneous breaking at the few TeV scale leads to a physical Nambu -Goldstone – boson the Diracon, denoted D – which is restricted by astrophysics and induces invisible Higgs decays such as h -> DD. The scheme provides a rich, yet very simple scenario for symmetry breaking studies at colliders such as the LHC.
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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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Reig, M., Valle, J. W. F., & Vaquera-Araujo, C. A. (2017). Unifying left-right symmetry and 331 electroweak theories. Phys. Lett. B, 766, 35–40.
Abstract: We propose a realistic theory based on the SU(3) c. SU(3) L. SU(3) R. U(1) Xgauge group which requires the number of families to match the number of colors. In the simplest realization neutrino masses arise from the canonical seesaw mechanism and their smallness correlates with the observed V-A nature of the weak force. Depending on the symmetry breaking path to the Standard Model one recovers either a left-right symmetric theory or one based on the SU(3) c. SU(3) L. U(1) symmetry as the “next” step towards new physics.
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Carcamo Hernandez, A. E., Kovalenko, S., Valle, J. W. F., & Vaquera-Araujo, C. A. (2017). Predictive Pati-Salam theory of fermion masses and mixing. J. High Energy Phys., 07(7), 118–25pp.
Abstract: We propose a Pati-Salam extension of the standard model incorporating a flavor symmetry based on the Delta (27) group. The theory realizes a realistic Froggatt-Nielsen picture of quark mixing and a predictive pattern of neutrino oscillations. We find that, for normal neutrino mass ordering, the atmospheric angle must lie in the higher octant, CP must be violated in oscillations, and there is a lower bound for the 0 nu beta beta decay rate. For the case of inverted mass ordering, we find that the lower atmospheric octant is preferred, and that CP can be conserved in oscillations. Neutrino masses arise from a low-scale seesaw mechanism, whose messengers can be produced by a Z' portal at the LHC.
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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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Nada, A., & Ramos, A. (2021). An analysis of systematic effects in finite size scaling studies using the gradient flow. Eur. Phys. J. C, 81(1), 1–19pp.
Abstract: We propose a new strategy for the determination of the step scaling function sigma (u) in finite size scaling studies using the gradient flow. In this approach the determination of sigma (u) is broken in two pieces: a change of the flow time at fixed physical size, and a change of the size of the system at fixed flow time. Using both perturbative arguments and a set of simulations in the pure gauge theory we show that this approach leads to a better control over the continuum extrapolations. Following this new proposal we determine the running coupling at high energies in the pure gauge theory and re-examine the determination of the Lambda -parameter, with special care on the perturbative truncation uncertainties.
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