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http://hdl.handle.net/10261/61
2016-05-05T06:59:02ZGeneralized mu-tau reflection symmetry and leptonic CP violation
http://hdl.handle.net/10261/131098
Title: Generalized mu-tau reflection symmetry and leptonic CP violation
Authors: Chen, Peng; Ding, Gui-Jun; González Canales, Felix; Valle, José W. F.
Abstract: We propose a generalized mu-tau reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle theta(23) and the “Dirac” CP violation phase delta(CP). Only in a specific limit our proposed CP transformation reduces to standard mu-tau reflection, for which theta(23) and delta(CP) are both maximal. The “Majorana” phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NO nu A and DUNE.
Description: 14 pages.- 9 figures2016-04-14T10:50:23ZUpdating neutrino magnetic moment constraints
http://hdl.handle.net/10261/131091
Title: Updating neutrino magnetic moment constraints
Authors: Cañas, Blanca Cecilia; Miranda, O. G.; Parada, Alexander; Tórtola, María Amparo; Valle, José W. F.
Abstract: In this paper we provide an updated analysis of the neutrino magnetic moments (NMMs), discussing both the constraints on the magnitudes of the three transition moments Lambda(i) and the role of the CP violating phases present both in the mixing matrix and in the NMM matrix. The scattering of solar neutrinos off electrons in Borexino provides the most stringent restrictions, due to its robust statistics and the low energies observed, below 1 MeV. Our new limit on the effective neutrino magnetic moment which follows from the most recent Borexino data is 3.1 x 10(-11) mu(B) at 90% C.L. This corresponds to the individual transition magnetic moment constraints: vertical bar Lambda(1)vertical bar <= 5.6 x10(-11)mu(B), vertical bar Lambda(2)vertical bar <= 4.0 x10(-11)mu(B), and vertical bar Lambda(3)vertical bar <= 3.1 x10(-11)mu B(90% C. L.), irrespective of any complex phase. Indeed, the incoherent admixture of neutrino mass eigenstates present in the solar flux makes Borexino insensitive to the Majorana phases present in the NMM matrix. For this reason we also provide a global analysis including the case of reactor and accelerator neutrino sources, presenting the resulting constraints for different values of the relevant CP phases. Improved reactor and accelerator neutrino experiments will be needed in order to underpin the full profile of the neutrino electromagnetic properties.
Description: 20 pages.- 4 figures.- Addendum on the limit from the Borexino data2016-04-14T10:08:10ZAre the B decay anomalies related to neutrino oscillations?
http://hdl.handle.net/10261/131086
Title: Are the B decay anomalies related to neutrino oscillations?
Authors: Boucenna, Mohamed Sofiane; Valle, José W. F.; Vicente, Avelino
Abstract: Neutrino oscillations are solidly established, with a hint of CP violation just emerging. Similarly, there are hints of lepton universality violation in b -> s transitions at the level of 2.6 sigma. By assuming that the unitary transformation between weak and mass charged leptons equals the leptonic mixing matrix measured in neutrino oscillation experiments, we predict several lepton flavor violating (LFV) B meson decays. We are led to the tantalizing possibility that some LFV branching ratios for B decays correlate with the leptonic CP phase delta characterizing neutrino oscillations. Moreover, we also consider implications for l(i) -> l(j)l(k)l(k) decays.
Description: 5 pages.- 2 figures.- v2: 1 ref. added.- v3: matches2016-04-14T09:29:50ZSensitivities to neutrino electromagnetic properties at the TEXONO experiment
http://hdl.handle.net/10261/131060
Title: Sensitivities to neutrino electromagnetic properties at the TEXONO experiment
Authors: Kosmas, T.S.; Miranda, O. G.; Papoulias, D.K.; Tórtola, María Amparo; Valle, José W. F.
Abstract: The possibility of measuring neutral-current coherent elastic neutrino nucleus scattering (CENNS) at the TEXONO experiment has opened high expectations towards probing exotic neutrino properties. Focusing on low threshold Germanium-based targets with kg-scale mass, we find a remarkable efficiency not only for detecting CENNS events due to the weak interaction, but also for probing novel electromagnetic neutrino interactions. Specifically, we demonstrate that such experiments are complementary in performing precision Standard Model tests as well as in shedding light on sub-leading effects due to neutrino magnetic moment and neutrino charge radius. This work employs realistic nuclear structure calculations based on the quasi-particle random phase approximation (QRPA) and takes into consideration the crucial quenching effect corrections. Such a treatment, in conjunction with a simple statistical analysis, shows that the attainable sensitivities are improved by one order of magnitude as compared to previous studies.
Description: 18 pages.- 4 figures.- 1 table2016-04-13T12:41:16Z