459,579 research outputs found

    Can the Lepton Flavor Mixing Matrix Be Symmetric?

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    Current neutrino oscillation data indicate that the 3x3 lepton flavor mixing matrix V is likely to be symmetric about its V_{e3}-V_{\mu 2}-V_{\tau 1} axis. This off-diagonal symmetry corresponds to three pairs of {\it congruent} unitarity triangles in the complex plane. Terrestrial matter effects can substantially modify the genuine CP-violating parameter and off-diagonal asymmetries of V in realistic long-baseline experiments of neutrino oscillations.Comment: RexTex 14 pages (4 PS figures). More discussions adde

    An Experiment and Detection Scheme for Cavity-based Cold Dark Matter Searches

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    A resonance detection scheme and some useful ideas for cavity-based searches of light cold dark matter particles (such as axions) are presented, as an effort to aid in the on-going endeavors in this direction as well as for future experiments, especially in possibly developing a table-top experiment. The scheme is based on our idea of a resonant detector, incorporating an integrated Tunnel Diode (TD) and a GaAs HEMT/HFET (High Electron Mobility Transistor/Heterogenous FET) transistor amplifier, weakly coupled to a cavity in a strong transverse magnetic field. The TD-amplifier combination is suggested as a sensitive and simple technique to facilitate resonance detection within the cavity while maintaining excellent noise performance, whereas our proposed Halbach magnet array could serve as a low-noise and permanent solution replacing the conventional electromagnets scheme. We present some preliminary test results which demonstrate resonance detection from simulated test signals in a small optimal axion mass range with superior Signal-to-Noise Ratios (SNR). Our suggested design also contains an overview of a simpler on-resonance dc signal read-out scheme replacing the complicated heterodyne readout. We believe that all these factors and our propositions could possibly improve or at least simplify the resonance detection and read-out in cavity-based DM particle detection searches (and other spectroscopy applications) and reduce the complications (and associated costs), in addition to reducing the electromagnetic interference and background.Comment: 22 pages, 7 figure

    Intrinsic Percolative Superconductivity in Heavily Overdoped High Temperature Superconductors

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    Magnetic measurements on heavily overdoped La2−xSrxCuO4La_{2-x}Sr_xCuO_4, Tl2Ba2CuO6Tl_2Ba_2CuO_6, Bi2Sr2CuO6Bi_2Sr_2CuO_6 and Bi2Sr2CaCu2O8Bi_2Sr_2CaCu_2O_8 single crystals reveal a new type magnetization hysteresis loops characterized by the vanishing of usual central peak near zero field. Since this effect has been observed in various systems with very different structural details, it reflects probably a generic behavior for all high temperature superconductors. This easy penetration of magnetic flux can be understood in the picture of percolative superconductivity due to the inhomogeneous electronic state in heavily overdoped regime.Comment: 4 pages, 5 figure

    A study of high frequency nonlinear combustion instability in baffled annular liquid propellant rocket motors, volume 1 Final report, 25 Aug. 1969 - 25 Sep. 1970

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    High frequency nonlinear combustion instability in baffled annular liquid propellant rocket engines - Vol.

    Analytical study of control devices for high amplitude combustion instability Quarterly report

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    Mathematical model and analysis of combustion processes in annular rocket engines for control of high amplitude combustion instabilit

    Corrections to the thermodynamics of Schwarzschild-Tangherlini black hole and the generalized uncertainty principle

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    We investigate the thermodynamics of Schwarzschild-Tangherlini black hole in the context of the generalized uncertainty principle. The corrections to the Hawking temperature, entropy and the heat capacity are obtained via the modified Hamilton-Jacobi equation. These modifications show that the GUP changes the evolution of Schwarzschild-Tangherlini black hole. Specially, the GUP effect becomes susceptible when the radius or mass of black hole approach to the order of Planck scale, it stops radiating and leads to black hole remnant. Meanwhile, the Planck scale remnant can be confirmed through the analysis of the heat capacity. Those phenomenons imply that the GUP may give a way to solve the information paradox. Besides, we also investigate the possibilities to observe the black hole at LHC, the results demonstrate that the black hole can not be produced in the recent LHC.Comment: 12 pages, 6 figure
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