1,753 research outputs found
Atmospheric and galactic tau neutrinos
Neutrinos with energy greater than GeV are copiously produced in the p(A,p)
interactions occurring in the earth atmosphere and in our galactic plane. A
comparison of the tau and mu neutrino flux in the presence of neutrino
oscillations from these two astrophysical sites is presented. It is pointed out
that the galactic plane tau neutrino flux dominates over the downward going
atmospheric tau neutrino flux at much lower energy value than that for the
dominance of the mu neutrino flux from these two sites. Future prospects for
possible observations of galactic tau neutrino flux are also briefly mentioned.Comment: 8 pages, 4 figures, invited talk given at CosPA 2003, 13-15 Nov,
2003, Taipei, Taiwa
Ultra-high energy cosmic neutrinos
Several cosmologically distant astrophysical sources may produce ultra-high
energy cosmic neutrinos (E > 10^6 GeV) of all flavors above the atmospheric
neutrino background. I study the effects of vacuum neutrino flavor mixing on
this cosmic neutrino flux. Prospects for observations of these ultra-high
energy cosmic neutrinos in large underwater/ice neutrino telescopes are also
briefly discussed.Comment: 3 pages, latex, talk given at the 8th Asia Pacific Physics Conference
(APPC2000), 7-10 August, 2000, Taipei, Taiwan (to appear in its proceedings
High Energy Astrophysical Tau Neutrinos: The Expectations
Aspects related to production, propagation and prospects for observationsof
high energy astrophysical tau neutrinos originating from some
representativeextra terrestrial sources such as atmosphere of earth, our
galactic plane as well as possibly from distantsites of gamma ray bursts in the
energy range 10^3 < E\GeV < 10^11 are reviewed.Comment: 4 pages, 3 figures, talk given at 12th International Symposium on
Very High Energy Cosmic Ray Interactions (XII ISVHERCI), 15-20 July, 2002,
Geneva, Switzerland [to appear in its proceedings to be published by Nucl.
Phys. B (Proc. Suppl.)
On non hadronic origin of high energy neutrinos
Some of the non hadronic interactions, such as the \eta resonance formation
in the \gamma \gamma interactions and the muon pair production in the e\gamma
interactions, are identified as possible source interactions for generating
high energy neutrinos in the cosmos.Comment: 9 pages, 1 figure, talk given at First NCTS Workshop on Astroparticle
Physics, 6-9 December, 2001, Kenting, Taiwan (to appear in its proceedings
edited by H. Athar, Guey-Lin Lin, and K.-W. Ng
Tau Neutrino Astronomy in GeV Energies
We point out the opportunity of the tau neutrino astronomy for the neutrino
energy E ranging between 10 GeV and 10^3 GeV. In this energy range, the
intrinsic tau neutrino production is suppressed relative to the intrinsic muon
neutrino production. Any sizable tau neutrino flux may thus arise because of
the \nu_{\mu}\to \nu_{\tau} neutrino oscillations only. It is demonstrated
that, in the presence of the neutrino oscillations, consideration of the
neutrino flavor dependence in the background atmospheric neutrino flux leads to
the drastically different prospects between the observation of the
astrophysical muon neutrinos and that of the astrophysical tau neutrinos.
Taking the galactic-plane neutrino flux as the targeted astrophysical source,
we have found that the galactic-plane tau neutrino flux dominates over the
atmospheric tau neutrino flux for E > 10 GeV. Hence, the galactic-plane can at
least in principle be seen through the tau neutrinos with energies just greater
than 10 GeV. In a sharp contrast, the galactic-plane muon neutrino flux is
overwhelmed by its atmospheric background until E > 10^6 GeV.Comment: major revision of text and two new figures, to appear in PR
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