185 research outputs found

    COHERENT constraints on nonstandard neutrino interactions

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    Coherent elastic neutrino-nucleus scattering consistent with the standard model has been observed by the COHERENT experiment. We study nonstandard neutrino interactions using the detected spectrum. For the case in which the nonstandard interactions (NSI) are induced by a vector mediator lighter than 50 MeV, we obtain constraints on the coupling of the mediator. For a heavier mediator, we find that degeneracies between the NSI parameters severely weaken the constraints. However, these degeneracies do not affect COHERENT constraints on the effective NSI parameters for matter propagation in the Earth.Comment: 11 pages, 4 figures. Version to appear in PL

    Partial quark-lepton universality and neutrino CP violation

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    We study a model with partial quark-lepton universality that can naturally arise in grand unified theories. We find that constraints on the model can be reduced to a single condition on the Dirac CP phase Ξ΄\delta in the neutrino sector. Using our current knowledge of the CKM and PMNS mixing matrices, we predict βˆ’32.4∘<Ξ΄<32.0∘-32.4^\circ < \delta < 32.0^\circ at 2Οƒ2\sigma.Comment: 8 pages, 1 figure. Version to appear in the special issue, "Neutrino Masses and Oscillations 2015", of Advances in High Energy Physic

    Neutrino seesaw mechanism with texture zeros

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    In the context of the Type I seesaw mechanism, we carry out a systematic study of the constraints that result from zeros in both the Dirac and right-handed Majorana neutrino mass matrices. We find that most constraints can be expressed in the standard form with one or two element/cofactor zeros alone, while there are 9 classes of nonstandard constraints. We show that all the constraints are stable under one-loop renormalization group running from the lightest right-handed neutrino mass scale to the electroweak scale. We study the predictions of the nonstandard constraints for the lightest neutrino mass, Dirac CP phase and neutrinoless double beta decay.Comment: 43 pages, 9 figures, 3 tables. Version to appear in NP

    Texture and Cofactor Zeros of the Neutrino Mass Matrix

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    We study Majorana neutrino mass matrices that have two texture zeros, or two cofactor zeros, or one texture zero and one cofactor zero. The two texture/cofactor zero conditions give four constraints, which in conjunction with the five measured oscillation parameters completely determine the nine independent real parameters of the neutrino mass matrix. We also study the implications that future measurements of neutrinoless double beta decay and the Dirac CP phase will have on these cases.Comment: 25 pages, 8 tables, 11 figures. Version to appear in JHE
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