2,137 research outputs found
A lower bound on the number of cosmic ray events required to measure source catalogue correlations
Recent analyses of cosmic ray arrival directions have resulted in evidence
for a positive correlation with active galactic nuclei positions that has weak
significance against an isotropic source distribution. In this paper, we
explore the sample size needed to measure a highly statistically significant
correlation to a parent source catalogue. We compare several scenarios for the
directional scattering of ultra-high energy cosmic rays given our current
knowledge of the galactic and intergalactic magnetic fields. We find
significant correlations are possible for a sample of 1000 cosmic ray
protons with energies above 60 EeV.Comment: 23 pages, 9 figure
A Passive Probe for Subsurface Oceans and Liquid Water in Jupiter's Icy Moons
We describe an interferometric reflectometer method for passive detection of
subsurface oceans and liquid water in Jovian icy moons using Jupiter's
decametric radio emission (DAM). The DAM flux density exceeds 3,000 times the
galactic background in the neighborhood of the Jovian icy moons, providing a
signal that could be used for passive radio sounding. An instrument located
between the icy moon and Jupiter could sample the DAM emission along with its
echoes reflected in the ice layer of the target moon. Cross-correlating the
direct emission with the echoes would provide a measurement of the ice shell
thickness along with its dielectric properties. The interferometric
reflectometer provides a simple solution to sub-Jovian radio sounding of ice
shells that is complementary to ice penetrating radar measurements better
suited to measurements in the anti-Jovian hemisphere that shadows Jupiter's
strong decametric emission. The passive nature of this technique also serves as
risk reduction in case of radar transmitter failure. The interferometric
reflectometer could operate with electrically short antennas, thus extending
ice depth measurements to lower frequencies, and potentially providing a deeper
view into the ice shells of Jovian moons.Comment: Submitted to Icaru
Prospects for High-Elevation Radio Detection of >100 PeV Tau Neutrinos
Tau neutrinos are expected to comprise roughly one third of both the
astrophysical and cosmogenic neutrino flux, but currently the flavor ratio is
poorly constrained and the expected flux at energies above eV is low.
We present a detector concept aimed at measuring the diffuse flux of tau
neutrinos in this energy range via a high-elevation mountaintop detector using
the radio technique. The detector searches for radio signals from upgoing air
showers generated by Earth-skimming tau neutrinos. Signals from several
antennas in a compact array are coherently summed at the trigger level,
permitting not only directional masking of anthropogenic backgrounds, but also
a low trigger threshold. This design takes advantage of both the large viewing
area available at high-elevation sites and the nearly full duty cycle available
to radio instruments. We present trade studies that consider the station
elevation, frequency band, number of antennas in the array, and the trigger
threshold to develop a highly efficient station design. Such a mountaintop
detector can achieve a factor of ten improvement in acceptance over existing
instruments with 100 independent stations. With 1000 stations and three years
of observation, it can achieve a sensitivity to an integrated
flux of GeV cm sr s, in the
range of the expected flux of all-flavor cosmogenic neutrinos assuming a pure
iron cosmic-ray composition.Comment: 26 pages, 11 figure
Neutrino propagation in the Earth and emerging charged leptons with
Ultra-high-energy neutrinos serve as messengers of some of the highest energy
astrophysical environments. Given that neutrinos are neutral and only interact
via weak interactions, neutrinos can emerge from sources, traverse astronomical
distances, and point back to their origins. Their weak interactions require
large target volumes for neutrino detection. Using the Earth as a neutrino
converter, terrestrial, sub-orbital, and satellite-based instruments are able
to detect signals of neutrino-induced extensive air showers. In this paper, we
describe the software code that simulates tau neutrino and
muon neutrino interactions in the Earth and predicts the spectrum of the
-lepton and muons that emerge. The outputs are lookup
tables of charged lepton exit probabilities and energies that can be used
directly or as inputs to the code designed to simulate
optical and radio signals from extensive air showers induced by the emerging
charged leptons. We describe the inputs to the code, demonstrate its
flexibility and show selected results for -lepton and muon exit
probabilities and energy distributions. The code is open
source, available on github.Comment: 42 pages, 21 figures, code available at
https://github.com/NuSpaceSim/nupypro
Pseudorapidity and transverse momentum dependence of flow harmonics in pPb and PbPb collisions
info:eu-repo/semantics/publishe
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