261 research outputs found
High Energy Tau Neutrinos
The intrinsic tau neutrino flux from cosmological and astrophysical sources
has usually been considered negligible in comparison to the electron and muon
neutrino fluxes. However, the inclusion of the tau neutrino component coming
from hadronic decay at the source can significantly modify the tau neutrino
spectrum expected at Earth. We report our results on the high energy tau
neutrino production and its implications for the observation of high energy
neutrino events.Comment: 3 pages, 3 figures. To appear in the Proceedings of TAUP2001,
September 8-12, 2001 - Gran Sasso Laboratory, Ital
The form of cosmic string cusps
We classify the possible shapes of cosmic string cusps and how they transform
under Lorentz boosts. A generic cusp can be brought into a form in which the
motion of the cusp tip lies in the plane of the cusp. The cusp whose motion is
perpendicular to this plane, considered by some authors, is a special case and
not the generic situation.
We redo the calculation of the energy in the region where the string overlaps
itself near a cusp, which is the maximum energy that can be released in
radiation. We take into account the motion of a generic cusp and the resulting
Lorentz contraction of the string core. The result is that the energy scales as
instead of the usual value of , where is the
string radius and and is the typical length scale of the string. Since for cosmological strings, the radiation is strongly suppressed and could
not be observed.Comment: 15 pages, ReVTex, 2 postscript figures with eps
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