2,512 research outputs found

    Range fluctuations of high energy muons passing through matter

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    The information about energy spectrum of sea level muons at high energies beyond magnetic spectrographs can be obtained from the underground intensity measurements if the fluctuations problems are solved. The correction factor R for the range fluctuations of high energy muons were calculated by analytical method of Zatsepin, where most probable energy loss parameter are used. It is shown that by using the R at great depth together with the slope, lambda, of the vertical depth-intensity (D-I) curve in the form of exp(-t/lambda), the spectral index, gamma, in the power law energy spectrum of muons at sea level can be obtained

    Energy spectra of high energy atmospheric neutrinos

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    Focusing on high energy neutrinos ( or = 1 TeV), a new calculation of atmospheric neutrino intensities was carried out taking into account EMC effects observed in P-A collisions by accelerator, recent measurement of primary cosmic ray spectrum and results of cosmic ray muon spectrum and charge ratio. Other features of the present calculation are (1) taking into account kinematics of three body decays of kaons and charm particles in diffusion equations and (2) taking into account energy dependence of kaon production

    Dynamics of Multiferroic Domain Wall in Spin-Cycloidal Ferroelectric DyMnO3_{3}

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    We report the dielectric dispersion of the giant magnetocapacitance (GMC) in multiferroic DyMnO3_{3} over a wide frequency range. The GMC is found to be attributable not to the softened electromagnon but to the electric-field-driven motion of multiferroic domain wall (DW). In contrast to conventional ferroelectric DWs, the present multiferroic DW motion holds extremely high relaxation rate of ∼\sim10710^{7} s−1^{-1} even at low temperatures. This mobile nature as well as the model simulation suggests that the multiferroic DW is not atomically thin as in ferroelectrics but thick, reflecting its magnetic origin.Comment: 4 pages, 4 figure

    New calculation of atmospheric neutrino fluxes

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    We have performed a one-dimensional Monte Carlo calculation of atmospheric neutrino fluxes in the energy range 0.05 GeV–20 GeV including muon polarization effects. It is shown that the calculated n m On e ratio does not appear sufficient to explain the Kamiokande data from sub-GeV to multi-GeV energy region. It is suggested that neutrino oscillations would provide a solution to the anomalous n m On e ratio

    A new ultra high energy gamma ray telescope at Ohya mine

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    The search for ultra high energy gamma rays coming from point sources is one of the main experimental aims. A fast air shower timing system was constructed at ICRR for the study of the angular resolution of the system and operated approximately half a year. The characteristics of the surface array of Ohya air shower telescope is described

    Large-Area Scintillator Hodoscope with 50 ps Timing Resolution Onboard BESS

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    We describe the design and performance of a large-area scintillator hodoscope onboard the BESS rigidity spectrometer; an instrument with an acceptance of 0.3 m^{2}sr. The hodoscope is configured such that 10 and 12 counters are respectively situated in upper and lower layers. Each counter is viewed from its ends by 2.5 inch fine-mesh photomultiplier tubes placed in a stray magnetic field of 0.2 Tesla. Various beam-test data are presented. Use of cosmic-ray muons at ground-level confirmed 50 ps timing resolution for each layer, giving an overall time-of-flight resolution of 70 ps rms using a pure Gaussian resolution function. Comparison with previous measurements on a similar scintillator hodoscope indicates good agreement with the scaling law that timing resolution is proportional to 1/Npe\sqrt{N_{\rm pe}}, where NpeN_{\rm pe} is the effective number of photoelectrons.Comment: 16 pages, 14 figure

    Bancroftian filariasis in Kwale District, Kenya

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    Objective: To determine the prevalence of Wuchereria bancrofti infection in an area designated for filariasis control trial.Design: A cross-sectional survey.Setting: Three villages in Kinango location, Kwale district, Coast Province, Kenya.Subjects/participants: Oral informed consent to participate was obtained from adults and parents or guardians of children below fifteen years of age.Main outcome measures: Microfilaraemia prevalences, microfilarial densities and clinical manifestations.Results: The overall prevalence of microfilaraemia in the population was 16.4%. The prevalence of microfilaraemia was age-dependent and the overall microfilarial density (MFD) was 69.4 mf/ml (geometric mean) and significantly higher in males (95.8 mf/ml) than in females (48.6 mf/ml) (p < 0.05). The prevalence of clinical signs of infection was also agedependent with elephantiasis being significantly higher in females (2.3%) than in males (0.9%) (p < 0.05). Among the males, the major clinical manifestation was hydrocele (10.4%).Conclusion: These findings show high prevalence of bancroftian filariasis in Kwale district and warrant similar studies followed by implementation of intervention measures to reduce transmission in all areas of endemicity in the Coast Province

    A search for massive neutral bosons in orthopositronium decay

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    We have searched for an exotic decay of orthopositronium into a single photon and a short-lived neutral boson in the hitherto unexplored mass region above 900 keV/c2{\rm keV}/{\it c}^{2}, by noting that this decay is one of few remaining candidates which could explain the discrepancy of the orthopositronium decay-rate. A high-resolution measurement of the associated photon energy spectrum was carried out with a germanium detector to search for a sharp peak from this two-body decay. Our negative result provides the upper-limits of\mbox{ }2.0×10−42.0 \times 10^{-4} on the branching ratio of such a decay in the mass region from 847 to 1013 keV/c2{\rm keV}/{\it c}^{2}, and excludes the possibility of this decay mode explaining the discrepancy in the orthopositronium decay-rate.Comment: a LaTeX file (text 7 pages) and a uuencoded gz-compressed PostScript file (text 7 pages + figures 4 pages
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