726 research outputs found

    Calculation of AGARD Wing 445.6 Flutter Using Navier-Stokes Aerodynamics

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    An unsteady, 3D, implicit upwind Euler/Navier-Stokes algorithm is here used to compute the flutter characteristics of Wing 445.6, the AGARD standard aeroelastic configuration for dynamic response, with a view to the discrepancy between Euler characteristics and experimental data. Attention is given to effects of fluid viscosity, structural damping, and number of structural model nodes. The flutter characteristics of the wing are determined using these unsteady generalized aerodynamic forces in a traditional V-g analysis. The V-g analysis indicates that fluid viscosity has a significant effect on the supersonic flutter boundary for this wing

    Polarization transfer in the 16^{16}O(p,pâ€Č)(p,p') reaction at forward angles and structure of the spin-dipole resonances

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    Cross sections and polarization transfer observables in the 16^{16}O(p,pâ€Č)(p,p') reactions at 392 MeV were measured at several angles between Ξlab=\theta_{lab}= 0∘^\circ and 14∘^\circ. The non-spin-flip (ΔS=0{\Delta}S=0) and spin-flip (ΔS=1{\Delta}S=1) strengths in transitions to several discrete states and broad resonances in 16^{16}O were extracted using a model-independent method. The giant resonances in the energy region of Ex=19−E_x=19-27 MeV were found to be predominantly excited by ΔL=1{\Delta}L=1 transitions. The strength distribution of spin-dipole transitions with ΔS=1{\Delta}S=1 and ΔL=1{\Delta}L=1 were deduced. The obtained distribution was compared with a recent shell model calculation. Experimental results are reasonably explained by distorted-wave impulse approximation calculations with the shell model wave functions.Comment: 28 pages RevTex, including 9 figures, to be published in Phys. Rev. C.; a typo in Eq. (3b) was correcte

    Solar neutrino measurements in Super-Kamiokande-I

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    The details of Super--Kamiokande--I's solar neutrino analysis are given. Solar neutrino measurement in Super--Kamiokande is a high statistics collection of 8^8B solar neutrinos via neutrino-electron scattering. The analysis method and results of the 1496 day data sample are presented. The final oscillation results for the data are also presented.Comment: 32pages, 57figures, submitted to Physical Review

    Evidence for an oscillatory signature in atmospheric neutrino oscillation

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    Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu_mu nu_tau neutrino oscillation parameters; 1.9x10^-3 < Delta m^2 < 3.0x10^-3 eV^2 and \sin^2(2theta) > 0.90 at 90% confidence level.Comment: 5 pages, 5 figures, submitted to PR

    Three flavor neutrino oscillation analysis of atmospheric neutrinos in Super-Kamiokande

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    We report on the results of a three-flavor oscillation analysis using Super-Kamiokande~I atmospheric neutrino data, with the assumption of one mass scale dominance (Δm122\Delta m_{12}^2==0). No significant flux change due to matter effect, which occurs when neutrinos propagate inside the Earth for Ξ13\theta_{13}≠\neq0, has been seen either in a multi-GeV Îœe\nu_e-rich sample or in a ΜΌ\nu_\mu-rich sample. Both normal and inverted mass hierarchy hypotheses are tested and both are consistent with observation. Using Super-Kamiokande data only, 2-dimensional 90 % confidence allowed regions are obtained: mixing angles are constrained to sin⁥2Ξ13<0.14\sin^2\theta_{13} < 0.14 and 0.37<sin⁥2Ξ23<0.650.37 < \sin^2\theta_{23} < 0.65 for the normal mass hierarchy. Weaker constraints, sin⁥2Ξ13<0.27\sin^2\theta_{13} < 0.27 and 0.37<sin⁥2Ξ23<0.690.37 < \sin^2\theta_{23} < 0.69, are obtained for the inverted mass hierarchy case.Comment: 7 figures, 3 table

    Search for nucleon decay via modes favored by supersymmetric grand unification models in Super-Kamiokande-I

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    We report the results for nucleon decay searches via modes favored by supersymmetric grand unified models in Super-Kamiokande. Using 1489 days of full Super-Kamiokande-I data, we searched for p→ΜˉK+p \to \bar{\nu} K^+, n→ΜˉK0n \to \bar{\nu} K^0, p→Ό+K0p \to \mu^+ K^0 and p→e+K0p \to e^+ K^0 modes. We found no evidence for nucleon decay in any of these modes. We set lower limits of partial nucleon lifetime 2.3×1033\times10^{33}, 1.3×1032\times10^{32}, 1.3×1033\times10^{33} and 1.0×1033\times10^{33} years at 90% confidence level for p→ΜˉK+p \to \bar{\nu} K^+, n→ΜˉK0n \to \bar{\nu} K^0, p→Ό+K0p \to \mu^+ K^0 and p→e+K0p \to e^+ K^0 modes, respectively. These results give a strong constraint on supersymmetric grand unification models.Comment: 14 pages, 13 figure

    Observation of the east-west anisotropy of the atmospheric neutrino flux

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    The east-west anisotropy, caused by the deflection of primary cosmic rays in the Earth's magnetic field, is observed for the first time in the flux of atmospheric neutrinos. Using a 45 kt-year exposure of the Super-Kamiokande detector, 552 e-like and 633 mu-like horizontally-going events are selected in the momentum range between 400 and 3000 MeV/c. The azimuthal distribution of e-like and mu-like events agrees with the expectation from atmospheric neutrino flux calculations that account for the geomagnetic field, verifying that the geomagnetic field effects in the production of atmospheric neutrinos in the GeV energy range are well understood.Comment: 8 pages,3 figures revtex, submitted to PR

    Search for Supernova Relic Neutrinos at Super-Kamiokande

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    A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type anti-neutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 nu_e bar cm^-2 s^-1. Additionally, an upper bound of 1.2 nu_e bar cm^-2 s^-1 was set for the supernova relic neutrino flux in the energy region E_nu > 19.3 MeV.Comment: 4 pages, 2 figures. Submitted to Physical Review Letters. New version includes corrections to Figure 1. Also, text has been shortened to conform with the space limitations of PR

    Search for Dark Matter WIMPs using Upward Through-going Muons in Super-Kamiokande

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    We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking for an excess of high energy muon neutrinos from WIMP annihilations in the Sun, the core of the Earth, and the Galactic Center, as compared to the number expected from the atmospheric neutrino background. No statistically significant excess was seen. We calculate flux limits in various angular cones around each of the above celestial objects. We obtain conservative model-independent upper limits on WIMP-nucleon cross-section as a function of WIMP mass and compare these results with the corresponding results from direct dark matter detection experiments.Comment: 10 pages, 14 figures, Submitted to Phys. Rev.
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