11,599 research outputs found

    A New Solution of the Solar Neutrino Flux

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    We report a new solution to explain the observed deficit of the solar neutrino flux by Homestake, Kamiokande II and III, GALLEX and SAGE experiments. We use the matter mixing and the helicity oscillation in the twisting magnetic fields in the sun. Our model predicts the short (seasonal) and long (11 years) time variations of the solar neutrino flux. Three kinds of data observed by Homestake, Kamiokande, GALLEX and SAGE detectors are reproduced well if the mixing angle and the squared mass difference are in the small area around sin22θ0.01\sin^2 2\theta \simeq 0.01 and Δm21.3×108eV2\Delta m^2\simeq 1.3\times 10^{-8}{\rm eV}^2.Comment: 13 pages and 4 figures (not included), in phyzzx, OU-HET-19

    Supersymmetry of M-Branes at Angles

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    We determine the possible fractions of supersymmetry preserved by two intersecting M-5-branes. These include the fractions 3/32 and 5/32 which have not occurred previously in intersecting brane configurations. Both occur in non-orthogonal pointlike intersections of M-5-branes but 5/32 supersymmetry is possible only for specific fixed angles.Comment: 11 pages, Late

    A BCS-BEC crossover in the extended Falicov-Kimball model: Variational cluster approach

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    We study the spontaneous symmetry breaking of the excitonic insulator state induced by the Coulomb interaction UU in the two-dimensional extended Falicov-Kimball model. Using the variational cluster approximation (VCA) and Hartree-Fock approximation (HFA), we evaluate the order parameter, single-particle excitation gap, momentum distribution functions, coherence length of excitons, and single-particle and anomalous excitation spectra, as a function of UU at zero temperature. We find that in the weak-to-intermediate coupling regime, the Fermi surface plays an essential role and calculated results can be understood in close correspondence with the BCS theory, whereas in the strong-coupling regime, the Fermi surface plays no role and results are consistent with the picture of BEC. Moreover, we find that HFA works well both in the weak- and strong-coupling regime, and that the difference between the results of VCA and HFA mostly appears in the intermediate-coupling regime. The reason for this is discussed from a viewpoint of the self-energy. We thereby clarify the excitonic insulator state that typifies either a BCS condensate of electron-hole pairs (weak-coupling regime) or a Bose-Einstein condensate of preformed excitons (strong-coupling regime).Comment: 11 pages, 9 figure

    CO(J=6-5) Observations of the Quasar SDSS1044-0125 at z = 5.8

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    We present a result of the quasar CO(J=6-5) observations of SDSSp J104433.04-012502.2 at z = 5.8. Ten-days observations with the Nobeyama Millimeter Array yielded an rms noise level of ~ 2.1 mJy/beam in a frequency range from 101.28 GHz to 101.99 GHz at a velocity resolution of 120 km/s. No significant clear emission line was detected in the observed field and frequency range. Three sigma upper limit on the CO(J=6-5) luminosity of the object is 2.8 x 10^10 K km/s pc^2, corresponding to a molecular gas mass of 1.2 x 10^11 Solar Mass, if a conversion factor of 4.5 Solar Mass /(K km/s pc^2) is adopted. The obtained upper limit on CO luminosity is slightly smaller than those observed in quasars at z=4-5 toward which CO emissions are detected.Comment: 4 pages, 3 figures, LaTeX2e, to appear in Publication of Astronomical Society of Japan (PASJ), Postscript file available at ftp://ftp.kusastro.kyoto-u.ac.jp/pub/iwata/preprint/sdss1044/sdss.ps.g