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Chatterjee, S. S., Masud, M., Pasquini, P., & Valle, J. W. F. (2017). Cornering the revamped BMV model with neutrino oscillation data. Phys. Lett. B, 774, 179–182.
Abstract: Using the latest global determination of neutrino oscillation parameters from [1] we examine the status of the simplest revamped version of the BMV (Babu-Ma-Valle) model, proposed in [2]. The model predicts a striking correlation between the “poorly determined” atmospheric angle 623 and CP phase Sep, leading to either maximal CP violation or none, depending on the preferred 623 octants. We determine the allowed BMV parameter regions and compare with the general three-neutrino oscillation scenario. We show that in the BMV model the higher octant is possible only at 99% C. L., a stronger rejection than found in the general case. By performing quantitative simulations of forthcoming DUNE and T2HK experiments, using only the four “well-measured” oscillation parameters and the indication for normal mass ordering, we also map out the potential of these experiments to corner the model. The resulting global sensitivities are given in a robust form, that holds irrespective of the true values of the oscillation parameters.
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Lattanzi, M., Gerbino, M., Freese, K., Kane, G., & Valle, J. W. F. (2020). Cornering (quasi) degenerate neutrinos with cosmology. J. High Energy Phys., 10(10), 213–24pp.
Abstract: In light of the improved sensitivities of cosmological observations, we examine the status of quasi-degenerate neutrino mass scenarios. Within the simplest extension of the standard cosmological model with massive neutrinos, we find that quasi-degenerate neutrinos are severely constrained by present cosmological data and neutrino oscillation experiments. We find that Planck 2018 observations of cosmic microwave background (CMB) anisotropies disfavour quasi-degenerate neutrino masses at 2.4 Gaussian sigma 's, while adding baryon acoustic oscillations (BAO) data brings the rejection to 5.9 sigma 's. The highest statistical significance with which one would be able to rule out quasi-degeneracy would arise if the sum of neutrino masses is Sigma m(v) = 60 meV (the minimum allowed by neutrino oscillation experiments); indeed a sensitivity of 15 meV, as expected from a combination of future cosmological probes, would further improve the rejection level up to 17 sigma. We discuss the robustness of these projections with respect to assumptions on the underlying cosmological model, and also compare them with bounds from beta decay endpoint and neutrinoless double beta decay studies.
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Dorame, L., Meloni, D., Morisi, S., Peinado, E., & Valle, J. W. F. (2012). Constraining neutrinoless double beta decay. Nucl. Phys. B, 861(3), 259–270.
Abstract: A class of discrete flavor-symmetry-based models predicts constrained neutrino mass matrix schemes that lead to specific neutrino mass sum-rules (MSR). We show how these theories may constrain the absolute scale of neutrino mass, leading in most of the cases to a lower bound on the neutrinoless double beta decay effective amplitude.
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Queiroz, F. S., Siqueira, C., & Valle, J. W. F. (2016). Constraining flavor changing interactions from LHC Run-2 dilepton bounds with vector mediators. Phys. Lett. B, 763, 269–274.
Abstract: Within the context of vector mediators, is a new signal observed in flavor changing interactions, particularly in the neutral mesons systems K-0 – (K) over bar (0), D-0 – (D) over bar (0) and B-0 – (B) over bar (0), consistent with dilepton resonance searches at the LHC? In the attempt to address this very simple question, we discuss the complementarity between flavor changing neutral current (FCNC) and dilepton resonance searches at the LHC run 2 at 13 TeV with 3.2 fb(-1) of integrated luminosity, in the context of vector mediators at tree level. Vector mediators, are often studied in the flavor changing framework, specially in the light of the recent LHCb anomaly observed at the rare B decay. However, the existence of stringent dilepton bound severely constrains flavor changing interactions, due to restrictive limits on the Z' mass. We discuss this interplay explicitly in the well motivated framework of a 3-3-1 scheme, where fermions and scalars are arranged in the fundamental representation of the weak SU(3) gauge group. Due to the paucity of relevant parameters, we conclude that dilepton data leave little room for a possible new physics signal stemming from these systems, unless a very peculiar texture parametrization is used in the diagonalization of the CKM matrix. In other words, if a signal is observed in such flavor changing interactions, it unlikely comes from a 3-3-1 model.
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Merle, A., Platscher, M., Rojas, N., Valle, J. W. F., & Vicente, A. (2016). Consistency of WIMP Dark Matter as radiative neutrino mass messenger. J. High Energy Phys., 07(7), 013–17pp.
Abstract: The scotogenic scenario provides an attractive approach to both Dark Matter and neutrino mass generation, in which the same symmetry that stabilises Dark Matter also ensures the radiative seesaw origin of neutrino mass. However the simplest scenario may suffer from inconsistencies arising from the spontaneous breaking of the underlying Z(2) symmetry. Here we show that the singlet-triplet extension of the simplest model naturally avoids this problem due to the presence of scalar triplets neutral under the Z(2) which affect the evolution of the couplings in the scalar sector. The scenario offers good prospects for direct WIMP Dark Matter detection through the nuclear recoil method.
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