3,095,722 research outputs found

    Limits on the Majorana neutrino mass in the 0.1 eV range

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    The Heidelberg-Moscow experiment gives the most stringent limit on the Majorana neutrino mass. After 24 kg yr of data with pulse shape measurements, we set a lower limit on the half-life of the neutrinoless double beta decay in 76Ge of T_1/2 > 5.7 * 10^{25} yr at 90% C.L., thus excluding an effective Majorana neutrino mass greater than 0.2 eV. This allows to set strong constraints on degenerate neutrino mass models.Comment: 6 pages (latex) including 3 postscript figures and 2 table

    New experimental limits on non-Newtonian forces in the micrometer-range

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    We report measurements of the short-range forces between two macroscopic gold-coated plates using a torsion pendulum. The force is measured for separations between 0.7 μ\mum and 7 μ\mum, and is well described by a combination of the Casimir force, including the finite-temperature correction, and an electrostatic force due to patch potentials on the plate surfaces. We use our data to place constraints on the Yukawa-type "new" forces predicted by theories with extra dimensions. We establish a new best bound for force ranges 0.4 μ\mum to 4 μ\mum, and, for forces mediated by gauge bosons propagating in (4+n)(4+n) dimensions and coupling to the baryon number, extract a (4+n)(4+n)-dimensional Planck scale lower limit of M>70M_*>70 TeV.Comment: 4 pages, 2 figure

    A local density functional for the short-range part of the electron-electron interaction

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    Motivated by recent suggestions --to split the electron-electron interaction into a short-range part, to be treated within the density functional theory, and a long-range part, to be handled by other techniques-- we compute, with a diffusion Monte Carlo method, the ground-state energy of a uniform electron gas with a modified, short-range-only electron-electron interaction \erfc(\mu r)/r, for different values of the cutoff parameter μ\mu and of the electron density. After deriving some exact limits, we propose an analytic representation of the correlation energy which accurately fits our Monte Carlo data and also includes, by construction, these exact limits, thus providing a reliable ``short-range local-density functional''.Comment: 7 pages, 3 figure

    Comments on "Limits on possible new nucleon monopole-dipole interactions from the spin relaxation rate of polarized 3^3He gas"

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    In the article "Limits on possible new nucleon monopole-dipole interactions from the spin relaxation rate of polarized 3^3He gas", new limits on short-range, Axion-like interactions are presented. In this comment it is shown that the theoretical treatement of the data overestimates the sensitivity of the proposed method. We provide the corrected limits

    Odometer of long-range sandpiles in the torus: mean behaviour and scaling limits

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    In \cite{Cipriani2016}, the authors proved that with the appropriate rescaling, the odometer of the (nearest neighbours) Divisible Sandpile in the unit torus converges to the bi-Laplacian field. Here, we study α\alpha-long-range divisible sandpiles similar to those introduced in \cite{Frometa2018}. We obtain that for α(0,2)\alpha \in (0,2), the limiting field is a fractional Gaussian field on the torus. However, for α[2,)\alpha \in [2,\infty), we recover the bi-Laplacian field. The central tool for our results is a careful study of the spectrum of the fractional Laplacian in the discrete torus. More specifically, we need the rate of divergence of such eigenvalues as we let the side length of the discrete torus goes to infinity. As a side result, we construct the fractional Laplacian built from a long-range random walk. Furthermore, we determine the order of the expected value of the odometer on the finite grid. \end{abstract}Comment: 35 pages, 4 figure

    First search for gravitational waves from the youngest known neutron star

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    We present a search for periodic gravitational waves from the neutron star in the supernova remnant Cassiopeia A. The search coherently analyzes data in a 12 day interval taken from the fifth science run of the Laser Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies from 100 to 300 Hz and covers a wide range of first and second frequency derivatives appropriate for the age of the remnant and for different spin-down mechanisms. No gravitational-wave signal was detected. Within the range of search frequencies, we set 95% confidence upper limits of (0.7–1.2) × 10^(−24) on the intrinsic gravitational-wave strain, (0.4–4) × 10^(−4) on the equatorial ellipticity of the neutron star, and 0.005–0.14 on the amplitude of r-mode oscillations of the neutron star. These direct upper limits beat indirect limits derived from energy conservation and enter the range of theoretical predictions involving crystalline exotic matter or runaway r-modes. This paper is also the first gravitational-wave search to present upper limits on the r-mode amplitude

    Analysis of proposed criteria for human response to vibration

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    The development of criteria for human vibration response is reviewed, including the evolution of the ISO standard 2631. The document is analyzed to show why its application to vehicle ride evaluation is strongly opposed. Alternative vertical horizontal limits for comfort are recommended in the ground vehicle ride frequency range above 1 Hz. These values are derived by correlating the absorbed power findings of Pradko and Lee with other established criteria. Special emphasis is placed on working limits in the frequency range of 1 to 10 Hz since this is the most significant area in ground vehicle ride evaluation
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