30,402 research outputs found
Potential constrains on Lorentz invariance violation from the HAWC TeV gamma-rays
Astrophysical scenarios provide a unique opportunity to test the possible
signatures of Lorentz Invariance Violation (LIV) due to the high energies and
the very long distances they involve. An isotropic correction to the photon
dispersion relation, by hypothetical Lorentz invariance violation, has a
consequence that photons of sufficient energy are unstable and decay very fast.
The High Altitude Water Cherenkov (HAWC) observatory is sensitive to gamma-rays
in the 100 GeV to 100 TeV energy range, making it a very useful tool to study
LIV. In this work we present potential stringent limits for the LIV energy
scale at first and second order correction by the potential observations of
primary very high energy photons in HAWC energy range.Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017),
Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution
Sigma theory for Bredon modules
We develop new invariants similar to the Bieri-Strebel-Neumann-Renz
invariants but in the category of Bredon modules (with respect to the class of
the finite subgroups of G). We prove that for virtually soluble groups of type
FP_{\infty} and finite extension of the Thompson group F the new invariants
coincide with the classical ones
Analysis of marketing systems on traditional bananas and plantains in Peru
Poster presented at Tropentag 2011 - Development on the Margin. Bonn (Germany), 3-7 Oct 2011
Effects of Lorentz invariance violation on cosmic ray photon emission and gamma ray decay processes
In this work, we use Lorentz invariance violation (LIV) introduced as a
generic modification to particle dispersion relations to study some
consequences of single photon emission, known as vacuum Cherenkov radiation,
and photon decay processes in cosmic and gamma rays. These processes are
forbidden in a Lorentz invariant theory but allowed under the hypothesis of
LIV. We show that the emission rate have a dependency on the cosmic ray primary
mass and the electric charge that could modify the UHECR spectrum. Furthermore,
LIV dramatically enhances photon decay into an electro-positron pair above
certain energy threshold. This last effect can then be used to set limits to
the LIV energy scale from the direct observation of very high energy cosmic
photon events by telescopes of gamma-rays.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Busan, Kore
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