114 research outputs found
A Faraway Quasar in the Direction of the Highest Energy Auger Event
The highest energy cosmic ray event reported by the Auger Observatory has an
energy of 148 EeV. It does not correlate with any nearby (z0.024) object
capable of originating such a high energy event. Intrigued by the fact that the
highest energy event ever recorded (by the Fly's Eye collaboration) points to a
faraway quasar with very high radio luminosity and large Faraday rotation
measurement, we have searched for a similar source for the Auger event. We find
that the Auger highest energy event points to a quasar with similar
characteristics to the one correlated to the Fly's Eye event. We also find the
same kind of correlation for one of the highest energy AGASA events. We
conclude that so far these types of quasars are the best source candidates for
both Auger and Fly's Eye highest energy events. We discuss a few exotic
candidates that could reach us from gigaparsec distances.Comment: 13 pages (version to be published in JCAP
Closing the Window on Strongly Interacting Dark Matter with IceCube
We use the recent results on dark matter searches of the 22-string IceCube
detector to probe the remaining allowed window for strongly interacting dark
matter in the mass range 10^4<m_X<10^15 GeV. We calculate the expected signal
in the 22-string IceCube detector from the annihilation ofsuch particles
captured in the Sun and compare it to the detected background. As a result, the
remaining allowed region in the mass versus cross sectionparameter space is
ruled out. We also show the expected sensitivity of the complete IceCube
detector with 86 strings.Comment: 5 pages, 7 figures. Uppdated figures 2 and 3 (y-axis normalization
and label) . Version accepted for publication in PR
Detection of Exotic Massive Hadrons in Ultra High Energy Cosmic Ray Telescopes
We investigate the detection of exotic massive strongly interacting hadrons
(uhecrons) in ultra high energy cosmic ray telescopes. The conclusion is that
experiments such as the Pierre Auger Observatory have the potential to detect
these particles. It is shown that uhecron showers have clear distinctive
features when compared to proton and nuclear showers. The simulation of uhecron
air showers, and its detection and reconstruction by fluorescence telescopes is
described. We determine basic cuts in observables that will separate uhecrons
from the cosmic ray bulk, assuming this is composed by protons. If these are
composed by heavier nucleus the separation will be much improved. We also
discuss photon induced showers. The complementarity between uhecron detection
in accelerator experiments is discussed.Comment: 9 page 9 figure
Effects of the Energy Error Distribution of Fluorescence Telescopes on the UHECR energy spectrum
The measurement of the ultra high energy cosmic ray (UHECR) spectrum is
strongly affected by uncertainties on the reconstructed energy. The
determination of the presence or absence of the GZK cutoff and its position in
the energy spectrum depends not only on high statistics but also on the shape
of the energy error distribution. Here we determine the energy error
distribution for fluorescence telescopes, based on a Monte Carlo simulation.
The HiRes and Auger fluorescence telescopes are simulated in detail. We analyze
the UHECR spectrum convolved with this energy error distribution. We compare
this spectrum with one convolved with a lognormal error distribution as well as
with a Gaussian error distribution. We show that the energy error distribution
for fluorescence detectors can not be represented by these known distributions.
We conclude that the convolved energy spectrum will be smeared but not enough
to affect the GZK cutoff detection. This conclusion stands for both HiRes and
Auger fluorescence telescopes. This result differs from the effect of the
energy error distribution obtained with ground detectors and reinforces the
importance of the fluorescence energy measurement. We also investigate the
effect of possible fluorescence yield measurement errors in the energy
spectrum.Comment: 24 pages, 11 figure
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