433 research outputs found

    On the Mass Eigenstate Composition of the 8B Neutrinos from the Sun

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    The present data of gallium experiments provide indirectly the only experimental limit on the fraction of ν2\nu_2 mass eigenstate for the 8^8B neutrinos from the Sun. However, if to use the experimental data alone, the fraction of ν2\nu_2 and, consequently, sin2θsolsin^2\theta_{sol} still is allowed to be varied within a rather broad range. The further experimental efforts are needed to clear this point.Comment: 13 pages, 1 figure, 1 table. Corrected version, published in JCAP04(2007)00

    Hadron energy response of the Iron Calorimeter detector at the India-based Neutrino Observatory

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    The results of a Monte Carlo simulation study of the hadron energy response for the magnetized Iron CALorimeter detector, ICAL, proposed to be located at the India-based Neutrino Observatory (INO) is presented. Using a GEANT4 modeling of the detector ICAL, interactions of atmospheric neutrinos with target nuclei are simulated. The detector response to hadrons propagating through it is investigated using the hadron hit multiplicity in the active detector elements. The detector response to charged pions of fixed energy is studied first, followed by the average response to the hadrons produced in atmospheric neutrino interactions using events simulated with the NUANCE event generator. The shape of the hit distribution is observed to fit the Vavilov distribution, which reduces to a Gaussian at high energies. In terms of the parameters of this distribution, we present the hadron energy resolution as a function of hadron energy, and the calibration of hadron energy as a function of the hit multiplicity. The energy resolution for hadrons is found to be in the range 85% (for 1GeV) -- 36% (for 15 GeV).Comment: 14 pages, 10 figures (24 eps files

    Solving Solar Neutrino Puzzle via LMA MSW Conversion

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    We analyze the existing solar neutrino experiment data and show the allowed regions. The result from SNO's salt phase itself restricts quite a lot the allowed region's area. Reactor neutrinos play an important role in determining oscillation parameters. KamLAND gives decisive conclusion on the solution to the solar neutrino puzzle, in particular, the spectral distortion in the 766.3 Ty KamLAND data gives another new improvement in the constraint of solar MSW-LMA solutions. We confirm that at 99.73% C.L. the high-LMA solution is excluded.Comment: 6 eps figure

    Pair Production of Fourth Family Charged Sleptons at e+ee^{+}e^{-} Colliders

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    We study the pair production of l~4\tilde{l}_{4}, which is the supersymmetric partner of the fourth family charged lepton, at the e+ee^{+}e^{-} colliders. It is shown that the investigation of this process at ILC/CLIC will give opportunity to differentiate the MSSM with three and four families.Comment: 6 pages, 2 figure

    Neutrino oscillations with disentanglement of a neutrino from its partners

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    We bring attention to the fact that in order to understand existing data on neutrino oscillations, and to design future experiments, it is imperative to appreciate the role of quantum entanglement. Once this is accounted for, the resulting energy-momentum conserving phenomenology requires a single new parameter related to disentanglement of a neutrino from its partners. This parameter may not be CP symmetric. We illustrate the new ideas, with potentially measurable effects, in the context of a novel experiment recently proposed by Gavrin, Gorbachev, Veretenkin, and Cleveland. The strongest impact of our ideas is on the resolution of various anomalies in neutrino oscillations and on neutrino propagation in astrophysical environments.Comment: 6 page

    Supernova Neutrinos and the LSND Evidence for Neutrino Oscillations

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    The observation of the νˉe\bar{\nu}_e energy spectrum from a supernova burst can provide constraints on neutrino oscillations. We derive formulas for adiabatic oscillations of supernova antineutrinos for a variety of 3- and 4-neutrino mixing schemes and mass hierarchies which are consistent with the LSND evidence for νˉμνˉe\bar{\nu}_{\mu}\to \bar{\nu}_e oscillations. Finally, we explore the constraints on these models and LSND given by the supernova SN1987A νˉe\bar{\nu}_e's observed by the Kamiokande-2 and IMB-3 detectors.Comment: 8 pages, 3 figures. Changes with respect to original version: appendix added; minor changes in text, figures, reference

    Neutrino mass spectrum and neutrinoless double beta decay

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    The relations between the effective Majorana mass of the electron neutrino, meem_{ee}, responsible for neutrinoless double beta decay, and the neutrino oscillation parameters are considered. We show that for any specific oscillation pattern meem_{ee} can take any value (from zero to the existing upper bound) for normal mass hierarchy and it can have a minimum for inverse hierarchy. This means that oscillation experiments cannot fix in general meem_{ee}. Mass ranges for meem_{ee} can be predicted in terms of oscillation parameters with additional assumptions about the level of degeneracy and the type of hierarchy of the neutrino mass spectrum. These predictions for meem_{ee} are systematically studied in the specific schemes of neutrino mass and flavor which explain the solar and atmospheric neutrino data. The contributions from individual mass eigenstates in terms of oscillation parameters have been quantified. We study the dependence of meem_{ee} on the non-oscillation parameters: the overall scale of the neutrino mass and the relative mass phases. We analyze how forthcoming oscillation experiments will improve the predictions for meem_{ee}. On the basis of these studies we evaluate the discovery potential of future \znbb decay searches. The role \znbb decay searches will play in the reconstruction of the neutrino mass spectrum is clarified. The key scales of meem_{ee}, which will lead to the discrimination among various schemes are: mee0.1m_{ee} \sim 0.1 eV and mee0.005m_{ee} \sim 0.005 eV.Comment: 47 pages, 35 figure

    Wind assessment for micro wind turbines in an urban environment

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    Wind flow in urban environments could be seen as a potential source of energy. This form of energy could be exploited by means of micro wind turbines placed along the existing infrastructures. To test this, an outdoor campaign was organised, which recorded the wind characteristics at different locations around a highway noise barrier in Delft, the Netherlands. The real-time data set was validated with a two-dimensional Computational Fluid Dynamics study. Both the influence of the high turbulence and the inflow angle on the positioning of the micro wind turbines are assessed for the case of perpendicular flow towards the plane of the noise barrier. Results indicated that integrating micro wind turbines with the noise barriers proves advantageous due to the flow velocity increment downstream. Lastly, a noise assessment was conducted in order to determine the optimal spacing between micro wind turbines, which impacts its social acceptance
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