1,695 research outputs found
High-energy Atmospheric Muon Flux Expected at India-Based Neutrino Observatory
We calculate the zenith-angle dependence of conventional and prompt
high-energy muon fluxes at India-Based Neutrino Observatory (INO) depth. This
study demonstrates a possibility to discriminate models of the charm
hadroproduction including the low-x QCD behaviour of hadronic cross-sections
relevant at very high energies.Comment: 10 pages. 8 figures, 3 table
Progresses in the validation of the FLUKA atmospheric neutrino flux calculations
The FLUKA calculation of the atmospheric neutrino fluxes have been
cross-checked by comparing predictions on lepton fluxes in atmosphere to
experimental data. The dependence of predicted neutrino fluxes on the shape and
normalization of primary spectrum is also investigatedComment: Presented at TAUP2001 (Sep. 8-12, Assergi, Italy). 5 pages, 1 figur
Gamma-hadron families and scaling violation
For three different interaction models we have simulated gamma-hadron families, including the detector (Pamir emulsion chamber) response. Rates of gamma families, hadrons, and hadron-gamma ratios were compared with experiments
Position and velocity space diffusion of test particles in stochastic electromagnetic fields
The two--dimensional diffusive dynamics of test particles in a random
electromagnetic field is studied. The synthetic electromagnetic fluctuations
are generated through randomly placed magnetised ``clouds'' oscillating with a
frequency . We investigate the mean square displacements of particles
in both position and velocity spaces. As increases the particles
undergo standard (Brownian--like) motion, anomalous diffusion and ballistic
motion in position space. Although in general the diffusion properties in
velocity space are not trivially related to those in position space, we find
that energization is present only when particles display anomalous diffusion in
position space. The anomalous character of the diffusion is only in the
non--standard values of the scaling exponents while the process is Gaussian.Comment: 10 pages, 4 figure
Asymptotic behaviour of the total cross section of p-p scattering and the Akeno cosmic ray data
I present a new determination of the total cross section for proton-proton
collisions from the recent Akeno results on absorption of the cosmic ray
protons in the p-Air collisions. Extrapolation to the SSC energy suggests
. I also comment on a possible
sensitivity of the p-Air cross section determinations to assumptions on the
inelasticity of nuclear collisions at high energy.Comment: . 6 pages, 0 figure
Probing Pseudo-Dirac Neutrino through Detection of Neutrino Induced Muons from GRB Neutrinos
The possibility to verify the pseudo-Dirac nature of neutrinos is
investigated here via the detection of ultra high energy neutrinos from distant
cosmological objects like GRBs. The very long baseline and the energy range
from TeV to EeV for such neutrinos invokes the likelihood to
probe very small pseude-Dirac splittings. The expected secondary muons from
such neutrinos that can be detected by a kilometer scale detector such as
ICECUBE is calculated. The pseudo-Dirac nature, if exists, will show a
considerable departure from flavour oscillation scenario in the total yield of
the secondary muons induced by such neutrinos.Comment: 11 pages, 3figure
Constraints on the origin of the ultra-high energy cosmic-rays using cosmic diffuse neutrino flux limits: An analytical approach
Astrophysical neutrinos are expected to be produced in the interactions of
ultra-high energy cosmic-rays with surrounding photons. The fluxes of the
astrophysical neutrinos are highly dependent on the characteristics of the
cosmic-ray sources, such as their cosmological distributions. We study possible
constraints on the properties of cosmic-ray sources in a model-independent way
using experimentally obtained diffuse neutrino flux above 100 PeV. The
semi-analytic formula is derived to estimate the cosmogenic neutrino fluxes as
functions of source evolution parameter and source extension in redshift. The
obtained formula converts the upper-limits on the neutrino fluxes into the
constraints on the cosmic-ray sources. It is found that the recently obtained
upper-limit on the cosmogenic neutrinos by IceCube constrains the scenarios
with strongly evolving ultra-high energy cosmic-ray sources, and the future
limits from an 1 km^3 scale detector are able to further constrain the
ultra-high energy cosmic-rays sources with evolutions comparable to the cosmic
star formation rate.Comment: 9 pages, 3 figures and 1 table. Accepted by Phys. Rev.
Flux of Atmospheric Neutrinos
Atmospheric neutrinos produced by cosmic-ray interactions in the atmosphere
are of interest for several reasons. As a beam for studies of neutrino
oscillations they cover a range of parameter space hitherto unexplored by
accelerator neutrino beams. The atmospheric neutrinos also constitute an
important background and calibration beam for neutrino astronomy and for the
search for proton decay and other rare processes. Here we review the literature
on calculations of atmospheric neutrinos over the full range of energy, but
with particular attention to the aspects important for neutrino oscillations.
Our goal is to assess how well the properties of atmospheric neutrinos are
known at present.Comment: 68 pages, 26 figures. With permission from the Annual Review of
Nuclear & Particle Science. Final version of this material is scheduled to
appear in the Annual Review of Nuclear & Particle Science Vol. 52, to be
published in December 2002 by Annual Reviews (http://annualreviews.org
Neutrino production through hadronic cascades in AGN accretion disks
We consider the production of neutrinos in active galactic nuclei (AGN)
through hadronic cascades. The initial, high energy nucleons are accelerated in
a source above the accretion disk around the central black hole. From the
source, the particles diffuse back to the disk and initiate hadronic cascades.
The observable output from the cascade are electromagnetic radiation and
neutrinos. We use the observed diffuse background X-ray luminosity, which
presumably results {}from this process, to predict the diffuse neutrino flux
close to existing limits from the Frejus experiment. The resulting neutrino
spectrum is down to the \GeV region. We discuss modifications of
this scenario which reduce the predicted neutrino flux.Comment: 12 Pages, LaTeX, TK 92 0
TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
The Geminga pulsar has long been one of the most intriguing MeV-GeV gamma-ray
point sources. We examine the implications of the recent Milagro detection of
extended, multi-TeV gamma-ray emission from Geminga, finding that this reveals
the existence of an ancient, powerful cosmic-ray accelerator that can plausibly
account for the multi-GeV positron excess that has evaded explanation. We
explore a number of testable predictions for gamma-ray and electron/positron
experiments (up to ~100 TeV) that can confirm the first "direct" detection of a
cosmic-ray source.Comment: 4 pages and 3 figures; Minor revisions, accepted for publication in
Physical Review Letter
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