397 research outputs found

    Estimation using sampled-data containing sequentially correlated noise

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    Filtering, prediction, and smoothing procedures for multi-stage linear dynamic systems using sampled data with sequentially correlated nois

    Determination of Strong-Interaction Widths and Shifts of Pionic X-Rays with a Crystal Spectrometer

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    Pionic 3d-2p atomic transitions in F, Na, and Mg have been studied using a bent crystal spectrometer. The pionic atoms were formed in the production target placed in the external proton beam of the Space Radiation Effects Laboratory synchrocyclotron. The observed energies and widths of the transitions are E=41679(3) eV and Γ=21(8) eV, E=62434(18) eV and Γ=22(80) eV, E=74389(9) eV and Γ=67(35) eV, in F, Na, and Mg, respectively. The results are compared with calculations based on a pion-nucleus optical potential

    Investigations of fast neutron production by 190 GeV/c muon interactions on different targets

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    The production of fast neutrons (1 MeV - 1 GeV) in high energy muon-nucleus interactions is poorly understood, yet it is fundamental to the understanding of the background in many underground experiments. The aim of the present experiment (CERN NA55) was to measure spallation neutrons produced by 190 GeV/c muons scattering on carbon, copper and lead targets. We have investigated the energy spectrum and angular distribution of spallation neutrons, and we report the result of our measurement of the neutron production differential cross section.Comment: 19 pages, 11 figures ep

    Results from the Palo Verde neutrino oscillation experiment

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    The ν̅e flux and spectrum have been measured at a distance of about 800 m from the reactors of the Palo Verde Nuclear Generating Station using a segmented Gd-loaded liquid scintillator detector. Correlated positron-neutron events from the reaction ν̅ep→e+n were recorded for a period of 200 d including 55 d with one of the three reactors off for refueling. Backgrounds were accounted for by making use of the reactor-on and reactor-off cycles, and also with a novel technique based on the difference between signal and background under reversal of the e+ and n portions of the events. A detailed description of the detector calibration, background subtraction, and data analysis is presented here. Results from the experiment show no evidence for neutrino oscillations. ν̅e→ν̅x oscillations were excluded at 90% C.L. for Δm2>1.12×10-3 eV2 for full mixing and sin22θ>0.21 for large Δm2. These results support the conclusion that the observed atmospheric neutrino oscillations do not involve νe

    Neutron production by cosmic-ray muons at shallow depth

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    The yield of neutrons produced by cosmic ray muons at a shallow depth of 32 meters of water equivalent has been measured. The Palo Verde neutrino detector, containing 11.3 tons of Gd loaded liquid scintillator and 3.5 tons of acrylic served as a target. The rate of one and two neutron captures was determined. Modeling the neutron capture efficiency allowed us to deduce the total yield of neutrons Ytot=(3.60±0.09±0.31)×10−5 Y_{tot} = (3.60 \pm 0.09 \pm 0.31) \times 10^{-5} neutrons per muon and g/cm2^2. This yield is consistent with previous measurements at similar depths.Comment: 12 pages, 3 figure

    Final results from the Palo Verde Neutrino Oscillation Experiment

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    The analysis and results are presented from the complete data set recorded at Palo Verde between September 1998 and July 2000. In the experiment, the \nuebar interaction rate has been measured at a distance of 750 and 890 m from the reactors of the Palo Verde Nuclear Generating Station for a total of 350 days, including 108 days with one of the three reactors off for refueling. Backgrounds were determined by (a) the swapswap technique based on the difference between signal and background under reversal of the positron and neutron parts of the correlated event and (b) making use of the conventional reactor-on and reactor-off cycles. There is no evidence for neutrino oscillation and the mode \nuebar\to\bar\nu_x was excluded at 90% CL for \dm>1.1\times10^{-3} eV2^2 at full mixing, and \sinq>0.17 at large \dm.Comment: 11 pages, 8 figure

    Final report on the search for neutrinoless double-β decay of 76Ge from the Gotthard underground experiment

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    We report here on the final results of a search for Ge-76 double-beta decay conducted in the Gotthard underground laboratory. The detector consists of an array of eight high-purity natural germanium crystals totaling 1095 cm^3 fiducial volume. The accumulated data set represents a sensitivity of 10.0 kg yr. No indication of neutrinoless double-beta decay was found. The measured half-life limits are T1/2(0+ --> 0+) > 6.0(3.3) x 10^(23) yr for the transition to the ground state and T1/2(0+ --> 2+) > 1.4(0.65) x 10^(23) yr for the transition to the first excited state at 68% (90%) C.L. From these results we derive an upper limit for the Majorana mass of the neutrino in the range of 1.8 to 6.7 eV depending on matrix-element calculations. The same results allow limits to be set for the right-handed-current parameters: < 2.2 x 10^(-8)
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