38 research outputs found
The homestake surface-underground scintillations: Description
Two new detectors are currently under construction at the Homestake Gold Mine a 140-ton Large Area Scintillation Detector (LASD) with an upper surface area of 130 square meters, a geometry factor (for an isotropic flux) of 1200 square meters, sr, and a depth of 4200 m.w.e.; and a surface air shower array consisting of 100 scintillator elements, each 3 square meters, spanning an area of approximately square kilometers. Underground, half of the LASD is currently running and collecting muon data; on the surface, the first section of the air shower array will begin operation in the spring of 1985. The detectors and their capabilities are described
Detection of a Cosmic Ray with Measured Energy Well Beyond the Expected Spectral Cutoff due to Cosmic Microwave Radiation
We report the detection of a 51-joule (320 +/- 90 EeV) cosmic ray by the
Fly's Eye air shower detector in Utah. This is substantially greater than the
energy of any previously reported cosmic ray. A Greisen-Zatsepin-Kuz'min cutoff
of the energy spectrum (due to pion photoproduction energy losses) should occur
below this energy unless the highest energy cosmic rays have traveled less than
about 30 Mpc. The error box for the arrival direction in galactic coordinates
is centered on b=9.6 deg, l=163.4 deg. The particle cascade reached a maximum
size near a depth of 815 g/cm^2 in the atmosphere, a depth which does not
uniquely identify the type of primary particle.Comment: uuencoded compressed postscript, 20 pages, to appear in ApJ (3/1/95
Matter Creation via Vacuum Fluctuations in the Early Universe and Observed Ultra-High Energy Cosmic Ray Events
Cosmic rays of the highest energy, above the Greisen-Zatsepin-Kuzmin cut-off
of the spectrum, may originate in decays of superheavy long-living X-particles.
These particles may be produced in the early Universe from vacuum fluctuations
during or after inflation and may constitute a considerable fraction of Cold
Dark Matter. We calculate numerically their abundance for a wide range of
models. X-particles are considered to be either bosons or fermions. Particles
that are several times heavier than inflaton, m_inflaton \approx 10^{13} GeV,
and were produced by this mechanism, can account for the critical mass in the
Universe naturally. In some cases induced isocurvature density fluctuations can
leave an imprint in anisotropy of cosmic microwave background radiation.Comment: LaTeX, 9 page