de Anda, F. J., Medina, O., Valle, J. W. F., & Vaquera-Araujo, C. A. (2022). Scotogenic Majorana neutrino masses in a predictive orbifold theory of flavor. Phys. Rev. D, 105(5), 055030–12pp.
Abstract: The use of extra space-time dimensions provides a promising approach to the flavor problem. The chosen compactification of a 6-dimensional orbifold implies a remnant family symmetry A4. This makes interesting predictions for quark and lepton masses, for neutrino oscillations and neutrinoless double beta decay, providing also a very good global description of all flavor observables. Due to an auxiliary Z4 symmetry, we implement a scotogenic Majorana neutrino mass generation mechanism with a viable WIMP dark matter candidate.
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Mandal, S., Miranda, O. G., Sanchez Garcia, G., Valle, J. W. F., & Xu, X. J. (2022). Toward deconstructing the simplest seesaw mechanism. Phys. Rev. D, 105(9), 095020–32pp.
Abstract: The triplet or type-II seesaw mechanism is the simplest way to endow neutrinos with mass in the Standard Model (SM). Here we review its associated theory and phenomenology, including restrictions from S, T, U parameters, neutrino experiments, charged lepton flavor violation as well as collider searches. We also examine restrictions coming from requiring consistency of electroweak symmetry breaking, i.e., perturbative unitarity and stability of the vacuum. Finally, we discuss novel effects associated to the scalar mediator of neutrino mass generation namely, (i) rare processes, e.g., l(alpha)-> l(beta)gamma decays, at the intensity frontier, and also (ii) four-lepton signatures in colliders at the high-energy frontier. These can be used to probe neutrino properties in an important way, providing a test of the absolute neutrino mass and mass ordering, as well as of the atmospheric octant. They may also provide the first evidence for charged lepton flavor violation in nature. In contrast, neutrino nonstandard interaction strengths are found to lie below current detectability.
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DUNE Collaboration(Abud, A. A. et al), Antonova, M., Barenboim, G., Cervera-Villanueva, A., De Romeri, V., Fernandez Menendez, P., et al. (2022). Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment. Phys. Rev. D, 105(7), 072006–32pp.
Abstract: The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-calendar years (kt-MW-CY), where calendar years include an assumption of 57% accelerator uptime based on past accelerator performance at Fermilab. The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 4 sigma (5 sigma) level with a 66 (100) kt-MW-CY far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters, with a median sensitivity of 3 sigma for almost all true delta(CP) values after only 24 kt-MW-CY. We also show that DUNE has the potential to make a robust measurement of CPV at a 3 sigma level with a 100 kt-MW-CY exposure for the maximally CP-violating values delta(CP) = +/-pi/2. Additionally, the dependence of DUNE's sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest.
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Addazi, A., Ricciardi, G., Scarlatella, S., Srivastava, R., & Valle, J. W. F. (2022). Interpreting B anomalies within an extended 331 gauge theory. Phys. Rev. D, 106(3), 035030–14pp.
Abstract: In light of the recent R-K(*) data on neutral current flavor anomalies in B -> K-(*())l(+)l(-) decays, we reexamine their quantitative interpretation in terms of an extended 331 gauge theory framework. We achieve this by adding two extra lepton species with novel 331 charges, while ensuring that the model remains anomaly-free. In contrast to the canonical 331 models, the gauge charges of the first and second lepton families differ from each other, allowing lepton-flavor universality violation. We further expand the model by adding the neutral fermions required to provide an adequate description for small neutrino masses.
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Chatterjee, S. S., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2022). Nonunitarity of the lepton mixing matrix at the European Spallation Source. Phys. Rev. D, 106(7), 075016–16pp.
Abstract: If neutrinos get mass through the exchange of lepton mediators, as in seesaw schemes, the neutrino appearance probabilities in oscillation experiments are modified due to effective nonunitarity of the lepton mixing matrix. This also leads to new CP phases and an ambiguity in underpinning the “conventional” phase of the three-neutrino paradigm. We study the CP sensitivities of various setups based at the European Spallation Source neutrino super-beam (ESSnuSB) experiment in the presence of nonunitarity. We also examine its potential in constraining the associated new physics parameters. Moreover, we show how the combination of DUNE and ESSnuSB can help further improve the sensitivities on the nonunitarity parameters.
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