3,449 research outputs found

    Results of a search for monopoles and tachyons in horizontal cosmic ray flux

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    A search for monopoles and tachyons at ground level was carried out using an arrangement consisting of an ionization calorimeter and two hodoscope detectors. No clear evidence for these particles was obtained. The flux of monopoles with velocities beta approximately 0.01 is found to be less than 5.1 x 10 to the minus 13th power square centimeters s(-1) sr(-1) (95% cl.). The upper limit on the tachyon flux density is set as a 6 x 10 the minus 9th power particle/square centimeter event

    Energy spectrum of cascade showers induced by cosmic ray muons in the range from 50 GeV to 5 TeV

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    The energy spectrum of cascade showers induced by electromagnetic interactions of high energy muons of horizontal cosmic ray flux in iron absorber was measured. The total observation time exceeded 22,000 hours. Both the energy spectrum and angular distributions of cascade showers are fairly described in terms of the usual muon generation processes, with a single power index of the parent meson spectrum over the muon energy range from 150 GeV to 5 TeV

    Weak interactions of supersymmetric staus at high energies

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    Neutrino telescopes may have the potential to detect the quasi-stable staus predicted by supersymmetric models. Detection depends on stau electromagnetic energy loss and weak interactions. We present results for the weak interaction contribution to the energy loss of high energy staus as they pass through rock. We show that the neutral current weak interaction contribution to the energy loss increases with energy, but it is much smaller than the photonuclear energy loss, however, the charged current contribution may become the dominant process above the energy of 109\sim 10^9 GeV, depending on the parameters of the model. As a consequence, the stau range may be reduced above 109\sim 10^9 GeV as compared to the range neglecting weak interactions. We contrast this with the tau range which is barely changed with the inclusion of charged current interactions.Comment: 7 pages, 8 figures, version to be publishe

    Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High Energies

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    We evaluate both the tau lepton energy loss produced by photonuclear interactions and the neutrino charged current cross section at ultra-high energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using different theoretical and phenomenological models for nucleon and nucleus structure functions. The theoretical uncertainty is estimated by taking different extrapolations of the structure function F2 to very low values of x, in the low and moderate Q2 range for the tau lepton interaction and at high Q2 for the neutrino-nucleus inelastic cross section. It is at these extremely low values of x where nuclear shadowing and parton saturation effects are unknown and could be stronger than usually considered. For tau and neutrino energies E=10^9 GeV we find uncertainties of a factor 4 for the tau energy loss and of a factor 2 for the charged current neutrino-nucleus cross section.Comment: 20 pages and 11 figure

    Application of oxide-metallic catalysts on valve metals for ecological catalysis

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    Запропоновано спосіб одержання оксидно-металевих каталізаторів методом одностадійного плазмово-електролітичного оксидування вентильних металів для знешкодження токсидів природного та техногенного походження. Обґрунтовано застосування оксидів мангану та кобальту як легуючих компонентів. Встановлено, що одержані оксидні покриви характеризуються високою каталітичною активністю в модельних реакціях конверсії токсичних компонентів, зокрема відпрацьованих газів двигунів внутрішнього згоряння

    High energy leptons from muons in transit

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    The differential energy distribution for electrons and taus produced from lepton pair production from muons in transit through materials is numerically evaluated. We use the differential cross section to calculate underground lepton fluxes from an incident atmospheric muon flux, considering contributions from both conventional and prompt fluxes. An approximate form for the charged current differential neutrino cross section is provided and used to calculate single lepton production from atmospheric neutrinos. We compare the fluxes of underground leptons produced from incident muons with those produced from incident neutrinos and photons from muon bremsstrahlung. We discuss their relevance for underground detectors.Comment: 11 pages, 9 figures v2: Revised to include the calculation of muon bremsstrahlung events in comparison to pair production events. 1 new figur
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