1,375 research outputs found
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
Weak Kaon Production off the Nucleon
The weak kaon production off the nucleon induced by neutrinos is studied at
the low and intermediate energies of interest for some ongoing and future
neutrino oscillation experiments. This process is also potentially important
for the analysis of proton decay experiments. We develop a microscopical model
based on the SU(3) chiral Lagrangians. The basic parameters of the model are
fpi, the pion decay constant, Cabibbo's angle, the proton and neutron magnetic
moments and the axial vector coupling constants for the baryons octet, D and F,
that are obtained from the analysis of the semileptonic decays of neutron and
hyperons. The studied mechanisms are the main source of kaon production for
neutrino energies up to 1.2 to 1.5 GeV for the various channels and the cross
sections are large enough to be amenable to be measured by experiments such as
Minerva and T2K
Distance and Similarity Measures for Soft Sets
In [P. Majumdar, S. K. Samanta, Similarity measure of soft sets, New
Mathematics and Natural Computation 4(1)(2008) 1-12], the authors use matrix
representation based distances of soft sets to introduce matching function and
distance based similarity measures. We first give counterexamples to show that
their Definition 2.7 and Lemma 3.5(3) contain errors, then improve their Lemma
4.4 making it a corllary of our result. The fundamental assumption of Majumdar
et al has been shown to be flawed. This motivates us to introduce set
operations based measures. We present a case (Example 28) where
Majumdar-Samanta similarity measure produces an erroneous result but the
measure proposed herein decides correctly. Several properties of the new
measures have been presented and finally the new similarity measures have been
applied to the problem of financial diagnosis of firms.Comment: 14 pages, accepted manuscript, to appear in New Mathematics and
Natural Computatio
Antineutrino induced antikaon production off the nucleon
The charged current antikaon production off nucleons induced by antineutrinos
is studied at low and intermediate energies. We extend here our previous
calculation on kaon production induced by neutrinos. We have developed a
microscopic model that starts from the SU(3) chiral Lagrangians and includes
background terms and the resonant mechanisms associated to the lowest lying
resonance in the channel, namely, the Sigma*(1385). Our results could be of
interest for the background estimation of various neutrino oscillation
experiments like MiniBooNE and SuperK. They can also be helpful for the planned
antineutrino experiments like MINERvA, NOvA and T2K phase II and for beta-beam
experiments with antineutrino energies around 1 GeV.Comment: 15 pages and 6 figures. This version matches accepted version for
publication in Physical Review
LazyFox: Fast and parallelized overlapping community detection in large graphs
The detection of communities in graph datasets provides insight about a
graph's underlying structure and is an important tool for various domains such
as social sciences, marketing, traffic forecast, and drug discovery. While most
existing algorithms provide fast approaches for community detection, their
results usually contain strictly separated communities. However, most datasets
would semantically allow for or even require overlapping communities that can
only be determined at much higher computational cost. We build on an efficient
algorithm, Fox, that detects such overlapping communities. Fox measures the
closeness of a node to a community by approximating the count of triangles
which that node forms with that community. We propose LazyFox, a multi-threaded
version of the Fox algorithm, which provides even faster detection without an
impact on community quality. This allows for the analyses of significantly
larger and more complex datasets. LazyFox enables overlapping community
detection on complex graph datasets with millions of nodes and billions of
edges in days instead of weeks. As part of this work, LazyFox's implementation
was published and is available as a tool under an MIT licence at
https://github.com/TimGarrels/LazyFox.Comment: 17 pages, 5 figure
Correlation Between the Total Small Bowel Length and Anthropometric Measures in Living Humans : Cross-Sectional Study
Open Access via Springer Compact AgreementPeer reviewedPublisher PD
Matter effects on neutrino oscillations in gravitational and magnetic fields
When neutrinos propagate in a background, their gravitational couplings are
modified by their weak interactions with the particles in the background. In a
medium that contains electrons but no muons or taons, the matter-induced
gravitational couplings of neutrinos are different for the various neutrino
flavors, and they must be taken into account in describing the phenomena
associated with the neutrino oscillations in the presence of strong
gravitational fields. Here we incorporate those couplings in that description,
including also the effects of a magnetic field, and consider the implications
that they have for the emission of high energy neutrinos in the vicinity of
Active Galactic Nuclei.Comment: Latex, 12 page
Neutrino Induced Upward Going Muons from a Gamma Ray Burst in a Neutrino Telescope of Km^2 Area
The number of neutrino induced upward going muons from a single Gamma Ray
Burst (GRB) expected to be detected by the proposed kilometer scale IceCube
detector at the South Pole location has been calculated. The effects of the
Lorentz factor, total energy of the GRB emitted in neutrinos and its distance
from the observer (red shift) on the number of neutrino events from the GRB
have been examined. The present investigation reveals that there is possibility
of exploring the early Universe with the proposed kilometer scale IceCube
neutrino telescope.Comment: 18pages, 5 figures. Physical Review D in pres
High Energy Neutrino Signals of Four Neutrino Mixing
We evaluate the upward shower and muon event rates for two characteristic
four neutrino mixing models for extragalactic neutrinos, as well as for the
atmospheric neutrinos, with energy thresholds of 1 TeV, 10 TeV and 100 TeV. We
show that by comparing the shower to muon event rates, one can distinguish
between oscillation and no-oscillation models. By measuring shower and muon
event rates for energy thresholds of 10 TeV and 100 TeV, and by considering
their ratio, it is possible to use extragalactic neutrino sources to determine
the type of four-flavor mixing pattern. We find that one to ten years of data
taking with kilometer-size detector has a very good chance of providing
valuable information about the physics beyond the Standard Model.Comment: version accepted for publication in Phys. Rev.
Enhanced signal of astrophysical tau neutrinos propagating through Earth
Earth absorbs \nue and \numu of energies above about 100 TeV. As is
well-known, although \nutau will also disappear through charged-current
interactions, the \nutau flux will be regenerated by prompt tau decays. We
show that this process also produces relatively large fluxes of secondary
\nube and \nubmu, greatly enhancing the detectability of the initial
\nutau. This is particularly important because at these energies \nutau is
a significant fraction of the expected astrophysical neutrino flux, and only a
tiny portion of the atmospheric neutrino flux.Comment: Four pages, two inline figure
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