5 research outputs found
Photon-axion mixing and ultra-high-energy cosmic rays from BL Lac type objects -- Shining light through the Universe
Photons may convert into axion like particles and back in the magnetic field
of various astrophysical objects, including active galaxies, clusters of
galaxies, intergalactic space and the Milky Way. This is a potential
explanation for the candidate neutral ultra-high-energy (E>10^18 eV) particles
from distant BL Lac type objects which have been observed by the High
Resolution Fly's Eye experiment. Axions of the same mass and coupling may
explain also TeV photons detected from distant blazars.Comment: Revtex 10 pages, 6 figures. V.2: QED dispersion effects taken into
account; principal results unchanged. V3: misprints and sqrt(4*pi) factors in
Gauss to eV conversion corrected; conclusions unchange
Searching for energetic cosmic axions in a laboratory experiment: testing the PVLAS anomaly
Astrophysical sources of energetic gamma rays provide the right conditions
for maximal mixing between (pseudo)scalar (axion-like) particles and photons if
their coupling is as strong as suggested by the PVLAS claim. This is
independent of whether or not the axion interaction is standard at all energies
or becomes supressed in the extreme conditions of the stellar interior. The
flux of such particles through the Earth could be observed using a metre long,
Tesla strength superconducting solenoid thus testing the axion interpretation
of the PVLAS anomaly. The rate of events in CAST caused by axions from the Crab
pulsar is also estimated for the PVLAS-favoured parameters.Comment: 5 pages, 3 figur
Axion Searches with Helioscopes and astrophysical signatures for axion(-like) particles
The first part reviews the working mechanisms, capabilities and performance
of axion helioscopes, including the achieved results so far. The 2nd part is
observationally driven. New simulation results obtained with the Geant4 code
reconstruct spectral shape of solar X-ray spectra, and their isotropic emission
and lateral size. The derived rst mass of the axion(-like) particles is ~10meV.
The axion interaction with magnetic field gradient is a generic theoretical
suggestion that could reconcile present limits with relevant solar X-ray
activity. A short outlook of the experimentally expanding solar axion field is
given.Comment: 31 pages, 18 figures. Aded 1 author, updated references. Accepted for
the special issue of NJP on dark matter (July 2009