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.
|
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.
|
de Anda, F. J., Antoniadis, I., Valle, J. W. F., & Vaquera-Araujo, C. A. (2020). Scotogenic dark matter in an orbifold theory of flavor. J. High Energy Phys., 10(10), 190–13pp.
Abstract: We propose a flavour theory in which the family symmetry results naturally from a six-dimensional orbifold compactification. “Diracness” of neutrinos is a consequence of the spacetime dimensionality, and the fact that right-handed neutrinos live in the bulk. Dark matter is incorporated in a scotogenic way, as a result of an auxiliary Z(3) symmetry, and its stability is associated to the conservation of a “dark parity” symmetry. The model leads naturally to a “golden” quark-lepton mass relation.
|
DUNE Collaboration(Abi, B. et al), Antonova, M., Barenboim, G., Cervera-Villanueva, A., De Romeri, V., Fernandez Menendez, P., et al. (2020). First results on ProtoDUNE-SP liquid argon time projection chamber performance from a beam test at the CERN Neutrino Platform. J. Instrum., 15(12), P12004–100pp.
Abstract: The ProtoDUNE-SP detector is a single-phase liquid argon time projection chamber with an active volume of 7.2 x 6.1 x 7.0 m(3). It is installed at the CERN Neutrino Platform in a specially-constructed beam that delivers charged pions, kaons, protons, muons and electrons with momenta in the range 0.3 GeV/c to 7 GeV/c. Beam line instrumentation provides accurate momentum measurements and particle identification. The ProtoDUNE-SP detector is a prototype for the first far detector module of the Deep Underground Neutrino Experiment, and it incorporates full-size components as designed for that module. This paper describes the beam line, the time projection chamber, the photon detectors, the cosmic-ray tagger, the signal processing and particle reconstruction. It presents the first results on ProtoDUNE-SP's performance, including noise and gain measurements, dE/dx calibration for muons, protons, pions and electrons, drift electron lifetime measurements, and photon detector noise, signal sensitivity and time resolution measurements. The measured values meet or exceed the specifications for the DUNE far detector, in several cases by large margins. ProtoDUNE-SP's successful operation starting in 2018 and its production of large samples of high-quality data demonstrate the effectiveness of the single-phase far detector design.
|
Miranda, O. G., Papoulias, D. K., Sanders, O., Tortola, M., & Valle, J. W. F. (2020). Future CEvNS experiments as probes of lepton unitarity and light sterile neutrinos. Phys. Rev. D, 102(11), 113014–14pp.
Abstract: We determine the sensitivities of short-baseline coherent elastic neutrino-nucleus scattering (CE nu NS) experiments using a pion decay at rest neutrino source as a probe for nonunitarity in the lepton sector, as expected in low-scale type-I seesaw schemes. We also identify the best configuration for probing light sterile neutrinos at future ton-scale liquid argon CE nu NS experiments, estimating the projected sensitivities on the sterile neutrino parameters. Possible experimental setups at the Spallation Neutron Source, Lujan facility and the European Spallation Source are discussed. Provided that systematic uncertainties remain under control, we find that CE nu NS experiments will be competitive with oscillation measurements in the long run.
|