905 research outputs found
Muon and Tau Neutrinos Spectra from Solar Flares
Solar neutrino flares and mixing are considered. Most power-full solar flare
as the ones occurred on 23th February 1956, September 29th 1989, 28th October
and on 2nd-4th November 2003 are sources of cosmic rays, X, gamma and neutrino
bursts. These flares took place both on front or in the edge and in the hidden
solar disk. The observed and estimated total flare energy should be a source of
a prompt secondary neutrino burst originated, by proton-proton-pion production
on the sun itself; a more delayed and spread neutrino flux signal arise by the
solar charged flare particles reaching the terrestrial atmosphere. Our first
estimates of neutrino signals in largest underground detectors hint for few
events in correlation with, gamma,radio onser. Our approximated spectra for
muons and taus from these rare solar eruption are shown over the most common
background. The muon and tau signature is very peculiar and characteristic over
electron and anti-electron neutrino fluxes. The rise of muon neutrinos will be
detectable above the minimal muon threshold of 113 MeV. The rarest tau
appearence will be possible only for hardest solar neutrino energies above
3.471 GeVComment: 14 pages, 4 figures, Vulcano Conference 200
Light Nuclei solving Auger puzzles. The Cen-A imprint
Ultra High Energy Cosmic Rays (UHECR) map at 60 EeV have been found recently
by AUGER group spreading anisotropy signatures in the sky. The result have been
interpreted as a manifestation of AGN sources ejecting protons at GZK edges
mostly from Super-galactic Plane. The result is surprising due to the absence
of much nearer Virgo cluster. Moreover, early GZK cut off in the spectra may be
better reconcile with light nuclei (than with protons). In addition a large
group (nearly a dozen) of events cluster suspiciously along Cen-A. Finally,
proton UHECR composition nature is in sharp disagreement with earlier AUGER
claim of a heavy nuclei dominance at 40 EeV. Therefore we interpret here the
signals as mostly UHECR light nuclei (He, Be, B, C, O), very possibly mostly
the lightest (He,Be) ones, ejected from nearest AGN Cen-A, UHECR smeared by
galactic magnetic fields, whose random vertical bending is overlapping with
super-galactic arm. The eventual AUGER misunderstanding took place because of
such a rare coincidence between the Super Galactic Plane (arm) and the smeared
(randomized) signals from Cen-A, bent orthogonally to the Galactic fields. Our
derivation verify the consistence of the random smearing angles for He, Be and
B, C, O, in reasonable agreement with the AUGER main group events around Cen-A.
Only few other rare events are spread elsewhere. The most collimated from Cen-A
are the lightest. The most spread the heavier. Consequently Cen-A is the best
candidate UHE neutrino tau observable by HEAT and AMIGA as enhanced AUGER array
at tens-hundred PeV energy. This model maybe soon tested by new events
clustering around the Cen-A and by composition imprint study.Comment: 4 pages, 5 figures
Ultrahigh energy neutrino scattering onto relic light neutrinos in galactic halo as a possible source of highest energy extragalactic cosmic rays
The diffuse relic neutrinos with light mass are transparent to Ultrahigh
energy (UHE) neutrinos at thousands EeV, born by photoproduction of pions by
UHE protons on relic 2.73 K BBR radiation and originated in AGNs at cosmic
distances. However these UHE s may interact with those (mainly heaviest
, and respective antineutrinos) clustered into HDM
galactic halos. UHE photons or protons, secondaries of scattering,
might be the final observed signature of such high-energy chain reactions and
may be responsible of the highest extragalactic cosmic-ray (CR) events. The
chain-reactions conversion efficiency, ramifications and energetics are
considered for the October 1991 CR event at 320 EeV observed by the Fly's Eye
detector in Utah. These quantities seem compatible with the distance, direction
and power (observed at MeV gamma energies) of the Seyfert galaxy MCG 8-11-11.
The interaction probability is favoured by at least three order of
magnitude with respect to a direct scattering onto the Earth atmosphere.
Therefore, it may better explain the extragalactic origin of the puzzling 320
EeV event, while offering indirect evidence of a hot dark galactic halo of
light (i.e., tens eV) neutrinos, probably of tau flavour.Comment: 25 pages, 1 figure minor corrections, updated references. In press in
AP
Possible Effects of the Existence of the 4th Generation Neutrino
The 4th generation of fermions predicted by the phenomenology of heterotic
string models can possess new strictly conserved charge, which leads, in
particular, to the hypothesis of the existence of the 4th generation massive
stable neutrino. The compatibility of this hypothesis with the results of
underground experiment DAMA searching for weakly interactive particles of dark
matter and with the EGRET measurements of galactic gamma--background at
energies above 1 GeV fixes the possible mass of the 4th neutrino at the value
about 50 GeV. The possibility to test the hypothesis in accelerator experiments
is considered. Positron signal from the annihilation of relic massive neutrinos
in the galactic halo is calculated and is shown to be accessible for planned
cosmic ray experiments.Comment: 10 pages, 4 PostScript figure, Latex2
GRBs-SN and SGR-X-Pulsar as blazing Jets
Old and recent puzzles of GRBs and SGRs find a solution with a model based on
the fast blazing of very collimated thin gamma Jets. Damped oscillating
afterglows in GRB030329 find a natural explanation assuming a very thin Jet
whose persistent activity and different angle of view maybe combined at once
with the Supernovae power and the apparent huge GRBs output. The same thin
beaming offer an understanding of the apparent SGR-Pulsar power connection. A
thin collimated precessing Gamma Jet model for both GRBs and SGRs, at their
different scaled luminosity (10^{44} - 10^{38}erg s^-1), explains the existence
of few identical energy spectra and time evolution of these sources leading to
a unified model. Their similarity with the huge precessing Jets in AGN, QSRs
and Radio-Galaxies inspires this smaller scale SGR-GRB model. The
spinning-precessing Jet explains the rare mysterious X-Ray precursors in GRBs
and SGRs events. Any large Gamma Jet off-axis beaming to the observer might
lead to the X-Flash events without any GRB signals, as the most recent
XRF030723. Its possible re-brightening would confirm the evidence of the
variable pointing of the jet in or off line towards the observer.
Indeed a multi-precessing Jet at peak activity in all bands may explain the
puzzling X or optical re-brightening bumps found in the GRB 021004, GRB030329
and the SGR 1900+ 14 on 27 August 1998 and once again on the 18 April 2001.
Rarest micro-quasars neutron star in our galaxy as SS433, and Herbig Haro
objects and Cir-X-1 describe these thin precessing Jet imprints in the
spectacular shapes of their relic nebulae.Comment: 10 pages, 10 figures, Vulcano Conference May 200
Signature of relic heavy stable neutrinos in underground experiments
Considering heavy stable neutrinos of 4th generation we calculate the relic
density of such neutrinos in the Universe. Taking into account the condensation
of heavy neutrinos in the Galaxy and applying the results of calculations to
experimental data from underground experiments on search for WIMPs in elastic
neutral current scattering on nuclei we found an exclusion region of neutrino
mass 60 GeV < m < 290 GeV. The bounds obtained from present underground
experiments while confirming the previous bounds derived from analysis of
cosmic ray spectra are more relible ones. We discuss also the first indication
of elastic scattering induced by WIMP in DAMA experiment finding a very narrow
window of neutrino mass 45 GeV < m < 50 GeV compatible with the possible signal
rate in the detector.Comment: 12 pages, 3 figure
Thermal effects on the absorption of ultra-high energy neutrinos by the cosmic neutrino background
We use the formalism of finite-temperature field theory to study the
interactions of ultra-high energy (UHE) cosmic neutrinos with the background of
relic neutrinos and to derive general expressions for the UHE neutrino
transmission probability. This approach allows us to take into account the
thermal effects introduced by the momentum distribution of the relic neutrinos.
We compare our results with the approximate expressions existing in the
literature and discuss the influence of thermal effects on the absorption dips
in the context of favoured neutrino mass schemes, as well as in the case of
clustered relic neutrinos.Comment: 3 pages, 2 figures. Prepared for the Proceedings of the 9th
International Conference on Topics in Astroparticle and Underground Physics
(TAUP 2005), Zaragoza (Spain), September 10-14, 200
SIMBIOS Project 1998 Annual Report
The purpose of this series of technical reports is to provide current documentation of the Sensor Intercomparison and Merger for Biological and Interdisciplinary Ocean Studies (SIMBIOS) Project activities, NASA Research Announcement (NRA) research status, satellite data processing, data product validation and field calibration. This documentation is necessary to ensure that critical information is related to the scientific community and NASA management. This critical information includes the technical difficulties and challenges of combining ocean color data from an array of independent satellite systems to form consistent and accurate global bio-optical time series products. This technical report is not meant to substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issues by an operational project
Evidence for a connection between the gamma-ray and the highest energy cosmic-ray emissions by BL Lacertae objects
A set of potentially gamma-ray--loud BL Lac objects is selected by
intersecting the EGRET and BL Lac catalogs. Of the resulting 14 objects, eight
are found to correlate with arrival directions of ultra--high-energy cosmic
rays (UHECRs), with significance of the order of 5 sigma. This suggests that
gamma-ray emission can be used as a distinctive feature of those BL Lac objects
that are capable of producing UHECR.Comment: 11 pages, 1 figure, version published in APJ Letter
Lightest Nuclei in UHECR versus Tau Neutrino Astronomy
UHECR may be either nucleons or nuclei; in the latter case the Lightest
Nuclei, as He, Li, Be, explains at best the absence of Virgo signals and the
crowding of events around Cen-A bent by galactic magnetic fields. This model
fit the observed nuclear mass composition discovered in AUGER. However UHECR
nucleons above GZK produce EeV neutrinos while Heavy Nuclei, as Fe UHECR do not
produce much. UHECR He nuclei at few tens EeV suffer nuclear fragmentation
(producing low energetic neutrino at tens PeVs) but it suffer anyway photo-pion
GZK suppression (leading to EeV neutrinos) once above one-few 10^{20} eV. Both
these cosmogenic UHE secondary neutrinos signals may influence usual predicted
GZK Tau Neutrino Astronomy in significant and detectable way; the role of
resonant antineutrino electron-electron leading to Tau air-shower may also
rise.Comment: 5 pages, 5 figures, CRIS 200
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