Escrihuela, F. J., Tortola, M., Valle, J. W. F., & Miranda, O. G. (2011). Global constraints on muon-neutrino nonstandard interactions. Phys. Rev. D, 83(9), 093002–8pp.
Abstract: The search for new interactions of neutrinos beyond those of the standard model may help to elucidate the mechanism responsible for neutrino masses. Here, we combine existing accelerator neutrino data with restrictions coming from a recent atmospheric neutrino data analysis in order to lift parameter degeneracies and improve limits on new interactions of muon neutrinos with quarks. In particular, we reconsider the results of the E-815 experiment at Fermilab (NuTeV) in view of a new evaluation of its systematic uncertainties. We find that, although constraints for muon neutrinos are better than those applicable to tau or electron neutrinos, they lie at the few X 10(-2) level, not as strong as previously believed. We briefly discuss prospects for further improvement.
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Escrihuela, F. J., Forero, D. V., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2015). On the description of nonunitary neutrino mixing. Phys. Rev. D, 92(5), 053009–16pp.
Abstract: Neutrino oscillations are well established and the relevant parameters determined with good precision, except for the CP phase, in terms of a unitary lepton mixing matrix. Seesaw extensions of the Standard Model predict unitarity deviations due to the admixture of heavy isosinglet neutrinos. We provide a complete description of the unitarity and universality deviations in the light-neutrino sector. Neutrino oscillation experiments involving electron or muon neutrinos and antineutrinos are fully described in terms of just three new real parameters and a new CP phase, in addition to the ones describing oscillations with unitary mixing. Using this formalism we describe the implications of nonunitarity for neutrino oscillations and summarize the model-independent constraints on heavy-neutrino couplings that arise from current experiments.
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Escrihuela, F. J., Forero, D. V., Miranda, O. G., Tortola, M., & Valle, J. W. F. (2017). Probing CP violation with non-unitary mixing in long-baseline neutrino oscillation experiments: DUNE as a case study. New J. Phys., 19, 093005–14pp.
Abstract: When neutrino masses arise from the exchange of neutral heavy leptons, as in most seesaw schemes, the effective lepton mixing matrix N describing neutrino propagation is non-unitary, hence neutrinos are not exactly orthonormal. New CP violation phases appear in N that could be confused with the standard phase delta(CP) characterizing the three neutrino paradigm. We study the potential of the long-baseline neutrino experiment DUNE in probing CP violation induced by the standard CP phase in the presence of non-unitarity. In order to accomplish this we develop our previous formalism, so as to take into account the neutrino interactions with the medium, important in long baseline experiments such as DUNE. We find that the expected CP sensitivity of DUNE is somewhat degraded with respect to that characterizing the standard unitary case. However the effect is weaker than might have been expected thanks mainly to the wide neutrino beam. We also investigate the sensitivity of DUNE to the parameters characterizing non-unitarity. In this case we find that there is no improvement expected with respect to the current situation, unless the near detector setup is revamped.
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Emmanuel-Costa, D., Simoes, C., & Tortola, M. (2013). The minimal adjoint-SU (5) x Z(4) GUT model. J. High Energy Phys., 10(10), 054–30pp.
Abstract: An extension of the adjoint SU (5) model with a flavour symmetry based on the Z(4) group is investigated. The Z(4) symmetry is introduced with the aim of leading the up-and down-quark mass matrices to the Nearest-Neighbour-Interaction form. As a consequence of the discrete symmetry embedded in the SU (5) gauge group, the charged lepton mass matrix also gets the same form. Within this model, light neutrinos get their masses through type-I, type-III and one-loop radiative seesaw mechanisms, implemented, respectively, via a singlet, a triplet and an octet from the adjoint fermionic 24 fields. It is demonstrated that the neutrino phenomenology forces the introduction of at least three 24 fermionic multiplets. The symmetry SU (5) x Z(4) allows only two viable zero textures for the effective neutrino mass matrix. It is showed that one texture is only compatible with normal hierarchy and the other with inverted hierarchy in the light neutrino mass spectrum. Finally, it is also demonstrated that Z(4) freezes out the possibility of proton decay through exchange of coloured Higgs triplets at tree-level.
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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). Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC. Eur. Phys. J. C, 82(7), 618–29pp.
Abstract: DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6 x 6 x 6 m(3) liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.
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