Bonilla, C., Nebot, M., Valle, J. W. F., & Srivastava, R. (2016). Flavor physics scenario for the 750 GeV diphoton anomaly. Phys. Rev. D, 93(7), 073009–5pp.
Abstract: A simple variant of a realistic flavor symmetry scheme for fermion masses and mixings provides a possible interpretation of the diphoton anomaly as an electroweak singlet “flavon.” The existence of TeV scale vectorlike T-quarks required to provide adequate values for Cabibbo-Kobayashi-Maskawa (CKM) parameters can also naturally account for the diphoton anomaly. Correlations between V-ub and V-cb with the vectorlike T-quark mass can be predicted. Should the diphoton anomaly survive in a future run, our proposed interpretation can also be tested in upcoming B and LHC studies.
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Chen, P., Ding, G. J., Gonzalez-Canales, F., & Valle, J. W. F. (2016). Classifying CP transformations according to their texture zeros: Theory and implications. Phys. Rev. D, 94(3), 033002–26pp.
Abstract: We provide a classification of generalized CP symmetries preserved by the neutrino mass matrix according to the number of zero entries in the associated transformation matrix. We determine the corresponding constrained form of the lepton mixing matrix, characterized by correlations between the mixing angles and the CP violating phases. We compare with the corresponding restrictions from current neutrino oscillation global fits and show that, in some cases, the Dirac CP phase characterizing oscillations is highly constrained. Implications for current and upcoming long baseline neutrino oscillation experiments T2K, NO nu A, and DUNE, as well as neutrinoless double beta decay experiments are discussed. We also study the cosmological implications of such schemes for leptogenesis.
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Reig, M., Valle, J. W. F., & Vaquera-Araujo, C. A. (2016). Realistic SU(3)(c) x SU(3)(L) x U(1)(X) model with a type II Dirac neutrino seesaw mechanism. Phys. Rev. D, 94(3), 033012–4pp.
Abstract: Here we propose a realistic SU(3)(c) circle times SU(3)(L) circle times U(1)(X) electroweak gauge model with enlarged Higgs sector. The scheme allows for the natural implementation of a type II seesaw mechanism for Dirac neutrinos, while charged lepton and quark masses are reproduced in a natural way thanks to the presence of new scalars. The new SU(3)(c) circle times SU(3)(L) circle times U(1)(X) energy scale characterizing neutrino mass generation could be accessible to the current LHC experiments.
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Ge, S. F., Pasquini, P., Tortola, M., & Valle, J. W. F. (2017). Measuring the leptonic CP phase in neutrino oscillations with nonunitary mixing. Phys. Rev. D, 95(3), 033005–14pp.
Abstract: Non-unitary neutrino mixing implies an extra CP violating phase that can fake the leptonic Dirac CP phase delta(CP) of the simplest three-neutrino mixing benchmark scheme. This would hinder the possibility of probing for CP violation in accelerator-type experiments. We take T2K and T2HK as examples to demonstrate the degeneracy between the “standard” (or “unitary”) and “nonunitary” CP phases. We find, under the assumption of nonunitary mixing, that their CP sensitivities severely deteriorate. Fortunately, the TNT2K proposal of supplementing T2(H)K with a μDAR source for better measurement of delta(CP) can partially break the CP degeneracy by probing both cos delta(CP) and sin delta(CP) dependences in the wide spectrum of the μDAR flux. We also show that the further addition of a near detector to the μDAR setup can eliminate the degeneracy completely.
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Pasquini, P., Centelles Chulia, S., & Valle, J. W. F. (2017). Neutrino oscillations from warped flavor symmetry: Predictions for long baseline experiments T2K, NOvA, and DUNE. Phys. Rev. D, 95(9), 095030–8pp.
Abstract: Here we study the pattern of neutrino oscillations emerging from a previously proposed warped standard model construction incorporating Delta(27) flavor symmetry [J. High Energy Phys. 01 (2016) 007]. In addition to a complete description of fermion masses, the model predicts the lepton mixing matrix in terms of two parameters. The good measurement of. theta(13) makes these two parameters tightly correlated, leading to an approximate one-parameter description of neutrino oscillations. We find secondary minima for the CP phase absent in the general unconstrained oscillation scenario and determine the fourfold degenerate sharp correlation between the physical CP phase delta(CP) and the atmospheric mixing angle. theta(23). This implies that maximal. theta(23) correlates with maximal leptonic CP violation. We perform a realistic estimate of the total neutrino and antineutrino event numbers expected at long baseline oscillation experiments T2K, NOvA, and the upcoming DUNE proposal. We show how an improved knowledge of the CP phase will probe the model in a significant way.
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