233 research outputs found
The diffuse neutrino flux from FR-II radio galaxies and blazars: A source property based estimate
Water and ice Cherenkov telescopes of the present and future aim for the
detection of a neutrino signal from extraterrestrial sources at energies E>PeV.
Some of the most promising extragalactic sources are Active Galactic Nuclei
(AGN). In this paper, the neutrino flux from two kinds of AGN sources will be
estimated assuming photohadronic interactions in the jet of the AGN. The first
analyzed sample contains FR-II radio galaxies while the second AGN type
examined are blazars. The result is highly dependent on the proton's index of
the energy spectrum. To normalize the spectrum, the connection between neutrino
and disk luminosity will be used by applying the jet-disk symbiosis model from
Falcke and Biermann (1995). The maximum proton energy and thus, also the
maximum neutrino energy of the source is connected to its disk luminosity,
which was shown by Lovelace (1976) and was confirmed by Falcke et al. (1995).Comment: 24 pages, 14 figures, to be published in Astroparticle Physic
The Muon Puzzle in cosmic-ray induced air showers and its connection to the Large Hadron Collider
High-energy cosmic rays are observed indirectly by detecting the extensive
air showers initiated in Earth's atmosphere. The interpretation of these
observations relies on accurate models of air shower physics, which is a
challenge and an opportunity to test QCD under extreme conditions. Air showers
are hadronic cascades, which eventually decay into muons. The muon number is a
key observable to infer the mass composition of cosmic rays. Air shower
simulations with state-of-the-art QCD models show a significant muon deficit
with respect to measurements; this is called the Muon Puzzle. The origin of
this discrepancy has been traced to the composition of secondary particles in
hadronic interactions. The muon discrepancy starts at the TeV scale, which
suggests that this change in hadron composition is observable at the Large
Hadron Collider. An effect that can potentially explain the puzzle has been
discovered at the LHC, but needs to be confirmed for forward produced hadrons
with LHCb, and with future data on oxygen beams.Comment: invited review submitted to Astrophysics and Space Scienc
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