3,449 research outputs found
Results of a search for monopoles and tachyons in horizontal cosmic ray flux
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
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
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 GeV, depending on the parameters of the model.
As a consequence, the stau range may be reduced above 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
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
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
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
- …