288 research outputs found
Observations of diffuse fluxes of cosmic neutrinos
In this contribution the current observational results for the diffuse flux
of high-energy astrophysical neutrinos are reviewed. In order to understand the
science implications, the measurements in different detection channels are
discussed and results are compared. The discussion focuses is the energy
spectrum, the flavor ratio and large scale anisotropy.Comment: Prepared for "Neutrino Astronomy - Current Status, Future Prospects"
(World Scientific) Edited by: Thomas Gaisser (University of Delaware, USA),
Albrecht Karle (University of Wisconsin-Madison, USA
Calculation of oscillation probabilities of atmospheric neutrinos using nuCraft
NuCraft (nucraft.hepforge.org) is an open-source Python project that
calculates neutrino oscillation probabilities for neutrinos from cosmic-ray
interactions in the atmosphere for their propagation through Earth. The
solution is obtained by numerically solving the Schr\"odinger equation. The
code supports arbitrary numbers of neutrino flavors including additional
sterile neutrinos, CP violation, arbitrary mass hierarchies, matter effects
with a configurable Earth model, and takes into account the production height
distribution of neutrinos in the Earth's atmosphere.Comment: submitted to Computer Physics Communication
Calculation of the Cherenkov light yield from electromagnetic cascades in ice with Geant4
In this work we investigate and parameterize the amount and angular
distribution of Cherenkov photons which are generated by electromagnetic
cascades in water or ice. We simulate electromagnetic cascades with Geant4 for
primary electrons, positrons and photons with energies ranging from 1 GeV to 10
TeV. We parameterize the total Cherenkov light yield as a function of energy,
the longitudinal evolution of the Cherenkov emission along the cascade-axis and
the angular distribution of photons. Furthermore, we investigate the
fluctuations of the total light yield, the fluctuations in azimuth and changes
of the emission with increasing age of the cascade
Effective field theory interpretation of searches for dark matter annihilation in the Sun with the IceCube Neutrino Observatory
We present a model-independent interpretation of searches for dark matter
annihilation in the Sun using an effective field theory approach. We identify a
set of effective operators contributing to spin-dependent scattering of dark
matter with protons in the non-relativistic limit and explore simple new
physics models which would give rise to such operators. Using the limits on the
spin-dependent scattering cross-section set by the IceCube collaboration in
their search for dark matter annihilation in the Sun, we derive limits on
effective couplings and corresponding masses of mediating particles. We show
that the effective field theory interpretation of the IceCube searches provides
constraints on dark matter complementary to those from relic density
observations and searches at the LHC. Finally, we discuss the impact of
astrophysical uncertainties on our results.Comment: 16 pages, 6 figures; Added references in v
Memory-function approach to the normal-state optical properties of the Bechgaard salt (TMTSF)_2PF_6
The gauge invariant, two-component optical conductivity model, with a
correlation gap structure related to the umklapp scattering processes, is
applied to the quasi-one-dimensional electronic systems and compared to the
recent measurements on the Bechgaard salt (TMTSF)_2PF_6. The optical response
of both the insulating and metallic state is found for the half-filled
conduction band, depending on the ratio between the correlation energy scale 2
\Delta^0_2 and the transfer integral in the direction perpendicular to the
conducting chains, t_{{\rm b}'}. The estimated value 2 \Delta^0_2/t_{{\rm b}'}
agrees reasonably well with the previous experimental and theoretical
conclusions. Parallel to the chains the thermally activated conduction
electrons in the insulating state are found to exhibit an universal behaviour,
accounting for the observed single-particle optical conductivity of the ordered
ground state of charge-density-wave systems. The band parameters and the
related damping energies suitable to the normal metallic state of (TMTSF)_2PF_6
are estimated from the measured spectra. Not only the spectral weights but also
the damping energies clearly indicate an opening of the correlation gap in the
charge excitation spectrumComment: 11 pages, 7 figure
Diffuse Emission of Galactic High-Energy Neutrinos from a Global Fit of Cosmic Rays
In the standard picture of galactic cosmic rays, a diffuse flux of
high-energy gamma-rays and neutrinos is produced from inelastic collisions of
cosmic ray nuclei with the interstellar gas. The neutrino flux is a guaranteed
signal for high-energy neutrino observatories such as IceCube, but has not been
found yet. Experimental searches for this flux constitute an important test of
the standard picture of galactic cosmic rays. Both the observation and
non-observation would allow important implications for the physics of cosmic
ray acceleration and transport. We present CRINGE, a new model of galactic
diffuse high-energy gamma-rays and neutrinos, fitted to recent cosmic ray data
from AMS-02, DAMPE, IceTop as well as KASCADE. We quantify the uncertainties
for the predicted emission from the cosmic ray model, but also from the choice
of source distribution, gas maps and cross-sections. We consider the
possibility of a contribution from unresolved sources. Our model predictions
exhibit significant deviations from older models. Our fiducial model is
available at https://doi.org/10.5281/zenodo.7373010 .Comment: 30 pages, 14 figures; references adde
Effective field theory interpretation of searches for dark matter annihilation in the Sun with the IceCube Neutrino Observatory
Afterpulse Measurements of R7081 Photomultipliers for the Double Chooz Experiment
We present the results of afterpulse measurements performed as qualification
test for 473 inner detector photomultipliers of the Double Chooz experiment.
The measurements include the determination of a total afterpulse occurrence
probability as well as an average time distribution of these pulses.
Additionally, more detailed measurements with different light sources and
simultaneous charge and timing measurements were performed with a few
photomultipliers to allow a more detailed understanding of the effect. The
results of all measurements are presented and discussed
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