229 research outputs found

    Robust Cosmological Bounds on Neutrinos and their Combination with Oscillation Results

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    We perform a global analysis of cosmological observables in generalized cosmologies which depart from Λ\LambdaCDM models by allowing non-vanishing curvature Ωk≠0\Omega_k\neq 0, dark energy with equation of state with ω≠−1\omega\neq -1, the presence of additional relativistic degrees of freedom ΔNrel\Delta N_{\rm rel}, and neutrino masses Ων≠0\Omega_\nu\neq 0. By combining the data from cosmic microwave background (CMB) experiments (in particular the latest results from WMAP-7), the present day Hubble constant (H0) measurement, the high-redshift Type-I supernovae (SN) results and the information from large scale structure (LSS) surveys, we determine the parameters in the 10-dimensional parameter space for such models. We present the results from the analysis when the full shape information from the LSS matter power spectrum (LSSPS) is included versus when only the corresponding distance measurement from the baryon acoustic oscillations (BAO) is accounted for. We compare the bounds on the neutrino mass scale in these generalized scenarios with those obtained for the 6+1 parameter analysis in ΛCDM+mν\Lambda{\rm CDM}+m_\nu models and we also study the dependence of those on the set of observables included in the analysis. Finally we combine these results with the information on neutrino mass differences and mixing from the global analysis of neutrino oscillation experiments and derive the presently allowed ranges for the two laboratory probes of the absolute scale of neutrino mass: the effective electron neutrino mass in single beta decay and the effective Majorana neutrino mass in neutrinoless ββ\beta\beta decay.Comment: 19 pages, 4 figures. Acknowledgments correcte

    Updated global fit to three neutrino mixing: status of the hints of theta13 > 0

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    We present an up-to-date global analysis of solar, atmospheric, reactor and accelerator neutrino data in the framework of three-neutrino oscillations. We discuss in detail the statistical significance of the observed "hint" of non-zero theta13 in the solar sector at the light of the latest experimental advances, such as the Borexino spectral data, the lower value of Gallium rate recently measured in SAGE, and the low energy threshold analysis of the combined SNO phase I and phase II. We also study the robustness of the results under changes of the inputs such as the choice of solar model fluxes and a possible modification of the Gallium capture cross-section as proposed by SAGE. In the atmospheric sector we focus on the latest results for nu_e appearance from MINOS and on the recent Super-Kamiokande results from the combined phases I, II and III, and we discuss their impact on the determination of theta13. Finally, we combine all the data into a global analysis and determine the presently allowed ranges of masses and mixing.Comment: 20 pages, 9 figures. Acknowledgments correcte

    Global fit to three neutrino mixing: critical look at present precision

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    We present an up-to-date global analysis of solar, atmospheric, reactor, and accelerator neutrino data in the framework of three-neutrino oscillations. We provide results on the determination of theta_13 from global data and discuss the dependence on the choice of reactor fluxes. We study in detail the statistical significance of a possible deviation of theta_23 from maximal mixing, the determination of its octant, the ordering of the mass states, and the sensitivity to the CP violating phase, and discuss the role of various complementary data sets in those respects.Comment: 23 pages, 7 figures. v3: final version to appear in JHEP. Updated results will be provided at http://www.nu-fit.or
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