125 research outputs found

    Inelastic Scattering of Tritium-Source Antineutrinos on Electrons of Germanium Atoms

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    Processes of the inelastic magnetic and weak scattering of tritium-beta-source antineutrinos on the bound electrons of a germanium atom are considered. The results obtained by calculating the spectra and cross sections are presented for the energy-transfer range between 1 eV and 18 keV.Comment: Latex, 7 pages, 8 ps figure

    Thermal detection of single e-h pairs in a biased silicon crystal detector

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    We demonstrate that individual electron-hole pairs are resolved in a 1 cm2^2 by 4 mm thick silicon crystal (0.93 g) operated at \sim35 mK. One side of the detector is patterned with two quasiparticle-trap-assisted electro-thermal-feedback transition edge sensor (QET) arrays held near ground potential. The other side contains a bias grid with 20\% coverage. Bias potentials up to ±\pm 160 V were used in the work reported here. A fiber optic provides 650~nm (1.9 eV) photons that each produce an electron-hole (eh+e^{-} h^{+}) pair in the crystal near the grid. The energy of the drifting charges is measured with a phonon sensor noise σ\sigma \sim0.09 eh+e^{-} h^{+} pair. The observed charge quantization is nearly identical for h+h^+'s or ee^-'s transported across the crystal.Comment: 4 journal pages, 5 figure

    On the Conductivity of a Magnetoactive Turbulent Plasma

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    The problem of determining the effective conductivity tensor of a magnetoactive turbulent plasma is considered in the approximation of isolated particles. Additional gyrotropicterms are shown to appear in the conductivity tensor in the presence of mean, nonzero magnetic helicity. The dispersion of propagating electro- magnetic waves changes, additional modes and additional rotation of the polarization plane appear, and the waves can be amplified. The properties acquired by plasma with helicity are similar those observed in chiral and bianisotropic electrodynamic media.Comment: 15 page

    Single spin asymmetry measurements for π0\pi^0 inclusive productions in p+pπ0+Xp+p_{\uparrow} \to \pi^0 + X and \pi^-+\p_{\uparrow}\to \pi^0+X reactions at 70 and 40 GeV respectively

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    The inclusive π0\pi^0 asymmetries were measured in reactions p+pπ0+Xp+p\uparrow \to \pi^0+X and π+pπ0+X\pi^-+p\uparrow \to \pi^0+X at 70 and 40 GeV/c respectively. The measurements were made at the central region (for the first reaction) and asymmetry is compatible with zero in the entire measured pTp_T region. For the second reaction the asymmetry is zero for small xFx_F region (0.4<xF<0.1,0.5<pT(GeV/c)<1.5-0.4<x_F<-0.1, 0.5<p_T(GeV/c) <1.5) and increases with growth of xF\mid x_F\mid. Averaged over the interval 0.8<xF<0.4,1<pT(GeV/c)<2-0.8<x_F<-0.4, 1<p_T(GeV/c)<2 the asymmetry was (13.8±3.8)-(13.8\pm 3.8)%.Comment: 4 pages, 2 figures; Presented at SPIN-2004 at Trieste, October 10-16,200

    Search for inelastic dark matter with the CDMS II experiment

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    Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (iDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Because of the occurrence of these events the constraints on the iDM parameter space are slightly less stringent than those from our previous analysis, which used an energy window of 10-100 keV.Comment: 10 pages, 10 figures, minor changes to match published version, conclusion unchange

    Measurement of the transverse target and beam-target asymmetries in η\eta meson photoproduction at MAMI

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    We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the γpηp\vec \gamma \vec p\to\eta p reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of η\eta meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.Comment: 5 pages, 3 figures, accepted for publication in PR
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