909 research outputs found
Tokyo Axion Helioscope
A new search result of the Tokyo axion helioscope is presented. The axion
helioscope consists of a dedicated cryogen-free 4T superconducting magnet with
an effective length of 2.3 m and PIN photodiodes as x-ray detectors. Solar
axions, if exist, would be converted into X-ray photons through the inverse
Primakoff process in the magnetic field. Conversion is coherently enhanced even
for massive axions by filling the conversion region with helium gas. The
present third phase measurement sets a new limit of
g_{a\gamma\gamma}<(5.6--13.4)\times10^{-10} GeV^{-1} for the axion mass of
0.84<m_a<1.0 eV at 95% confidence level.Comment: 4th Patras Workshop on Axions, WIMPs and WISP
Search for Hidden photons with Sumico
We searched for solar hidden photons in the visible photon energy range using
a hidden photon detector add-on attached to Sumico. It consists of a parabolic
mirror of dia. 0.5m and f=1m installed in a vacuum chamber, and a low noise
photomultiplier tube at the focal point. No evidence for the existence of
hidden photons was found in the latest measurement giving a new limit on the
photon-hidden photon mixing parameter in the hidden photon mass range
0.001-1eV.Comment: 6 pages. Contributed to the 9th Patras Workshop on Axions, WIMPs and
WISPs, Mainz, June 24-28, 201
The structure of EAS at E 0.1 EeV
The ratio of extensive air showers (EAS) total shower energy in the electromagnetic channel (E em) to the size of the shower at maximum development (N max) from a direct measurement of shower longitudinal development using the air fluorescence technique was calculated. The values are not inconsistent with values based upon track length integrals of the Gaisser-Hillas formula for shower development or the known relation between shower energy and size at maximum for pure electromagnetic cascades. Using Linsley's estimates for undetected shower energy based on an analysis of a wide variety of cosmic ray data, the following relation for total shower energy E vs N max is obtained. The Gaisser Hillas implied undetected shower energy fractions
Arrival directions of cosmic rays of E .4 EeV
The anisotropy of cosmic rays observed by the Utah Fly's Eye detector has been studied. Emphasis has been placed on examining distributions of events in galactic coordinates. No statistically significant departure from isotropy has been observed for energies greater than 0.4 EeV (1 EeV = 10 to the 18th power eV). Results of the standard harmonic analysis in right ascension are also presented
500 TeV gamma rays from Hercules X-1
A signal (chance probability = .0002) with the 1.24 s period of Hercules X-1 has been observed using the Utah Fly's Eye. The signal's relatively long period and high shower energy conflict with some popular models of particle acceleration by pulsars. Optical and X-ray data suggest a picture in which energetic particles produce multi-TeV gamma rays by collisions with Hercules X-1's accretion disk
Limits on deeply penetrating particles in the 10(17) eV cosmic ray flux
Deeply penetrating particles in the 10 to the 17th power eV cosmic ray flux were investigated. No such events were found in 8.2 x 10 to the 6th power sec of running time. Limits were set on the following: quark-matter in the primary cosmic ray flux; long-lived, weakly interacting particles produced in p-air collisions; the astrophysical neutrino flux. In particular, the neutrino flux limit at 10 to the 17th power eV implies that z, the red shift of maximum activity is 10 in the model of Hill and Schramm
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