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Bonilla, C., Lamprea, J. M., Peinado, E., & Valle, J. W. F. (2018). Flavour-symmetric type-II Dirac neutrino seesaw mechanism. Phys. Lett. B, 779, 257–261.
Abstract: We propose a Standard Model extension with underlying A(4) 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[ 1] we derive restrictions on the oscillation parameters, such as a correlation between delta(CP) and m(nu lightest).
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Bonilla, C., Ma, E., Peinado, E., & Valle, J. W. F. (2016). Two-loop Dirac neutrino mass and WIMP dark matter. Phys. Lett. B, 762, 214–218.
Abstract: 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 Diraconthat 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.
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Bonilla, C., Romao, J. C., & Valle, J. W. F. (2016). Electroweak breaking and neutrino mass: `invisible' Higgs decays at the LHC (type II seesaw). New J. Phys., 18, 033033–21pp.
Abstract: Neutrino mass generation through the Higgs mechanism not only suggests the need to reconsider the physics of electroweak symmetry breaking from a new perspective, but also provides a new theoretically consistent and experimentally viable paradigm. We illustrate this by describing the main features of the electroweak symmetry breaking sector of the simplest type-II seesaw model with spontaneous breaking of lepton number. After reviewing the relevant `theoretical' and astrophysical restrictions on the Higgs sector, we perform an analysis of the sensitivities of Higgs Boson searches at the ongoing ATLAS and CMS experiments at the LHC, including not only the new contributions to the decay channels present in the standard model (SM) but also genuinely non-SM Higgs Boson decays, such as `invisible' Higgs Boson decays to majorons. We find sensitivities that are likely to be reached at the upcoming run of the experiments.
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de Salas, P. F., Gariazzo, S., Mena, O., Ternes, C. A., & Tortola, M. (2018). Neutrino Mass Ordering From Oscillations and Beyond: 2018 Status and Future Prospects. Front. Astron. Space Sci., 5, 36–50pp.
Abstract: The ordering of the neutrino masses is a crucial input for a deep understanding of flavor physics, and its determination may provide the key to establish the relationship among the lepton masses and mixings and their analogous properties in the quark sector. The extraction of the neutrino mass ordering is a data-driven field expected to evolve very rapidly in the next decade. In this review, we both analyse the present status and describe the physics of subsequent prospects. Firstly, the different current available tools to measure the neutrino mass ordering are described. Namely, reactor, long-baseline (accelerator and atmospheric) neutrino beams, laboratory searches for beta and neutrinoless double beta decays and observations of the cosmic background radiation and the large scale structure of the universe are carefully reviewed. Secondly, the results from an up-to-date comprehensive global fit are reported: the Bayesian analysis to the 2018 publicly available oscillation and cosmological data sets provides strong evidence for the normal neutrino mass ordering vs. the inverted scenario, with a significance of 3.5 standard deviations. This preference for the normal neutrino mass ordering is mostly due to neutrino oscillation measurements. Finally, we shall also emphasize the future perspectives for unveiling the neutrinomass ordering. In this regard, apart from describing the expectations from the aforementioned probes, we also focus on those arising from alternative and novel methods, as 21 cm cosmology, core-collapse supernova neutrinos and the direct detection of relic neutrinos.
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Tortola, M. (2013). Status of three-neutrino oscillation parameters. Fortschritte Phys.-Prog. Phys., 61(4-5), 427–440.
Abstract: Here we review the current status of global fits to neutrino oscillation data within the three-flavour framework. In our analysis we include the most recent data from solar and atmospheric neutrino experiments as well as the latest results from the long-baseline accelerator neutrino experiments and the recent measurements of reactor neutrino disappearance reported by Double Chooz, Daya Bay and RENO. We present updated determinations for the two neutrino mass splittings and the three mixing angles responsible for neutrino oscillations that, for the first time, have all been measured with 1 sigma accuracies ranging from 3 to 15%. A weak sensitivity for the CP violating phase is also reported from the global analysis.
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