High Resolution Fly's Eye - status and preliminary results on cosmic ray composition above 10^18 eV

Journal ArticleWe describe the current status of the High Resolution Fly's Eye detector. Event reconstruction and associated systematics for stereo reconstruction are discussed and recent preliminary results on the study of the composition of ultra-high energy cosmic rays by the Xmax method are presented. These results indicate that the composition of cosmic rays becomes predominantly light near 101 9 eV and beyond

Ultra high energy ντ detection with a cosmic ray tau neutrino telescope used in fluorescence/Cerenkov light detection

ManuscriptWe have investigated the possibility of ντ detection using Cosmic Ray Tau Neutrino Telescope (CRTNT) based on air shower fluorescence/Cerenkov light detector techniques. This approach requires an interaction of a νг with material such as a mountain or the earth's crust. lepton produced in the charged current interaction must escape from the earth and then decay and initiate a shower in the air. The probability for the conversion from νг to air shower has been calculated for an energy range from 1 PeV to 10 EeV. An air shower simulation program has been developed using the simulation package Corsika. The trigger efficiency has been estimated for a CRTNT detector similar to the HiRes/Dice detector in the shadow of Mt. Wheeler in Nevada, USA. A rate of about 8 triggered events per year is expected for the AGN neutrino source model with an optimized configuration and duty cycle of the detector

Search for new particles at the alternating-gradient-synchrotron beam dump

Journal ArticleThis paper presents results of a beam-dump experiment performed at the Brookhaven alternating-gradient synchrotron to search for prompt sources of neutrinos and axionlike particles. We observe no excess of vµ or events, and no excess in neutral-current events over that expected from neutrinos from ir and K decays. We report on limits of prompt particle-production cross sections and lifetimes

Single-pion production in neutrino and antineutrino reactions

Journal ArticleWe have studied the neutral-current reactions vµN→vµN'rr0 and vµN→vµN'π0 and compared them to the charged-current reactions vµN→ µ-N"π0 and vµN → µ+N"π0 . We have measured the ratios R0' =(vµN- vµN'π0)/2σ(vµN→µ+N''π0) and R0' = O(vµN→vµN'π0)/2σ(vµN(vuN→u+N"π) to be 0.17 ± 0.04 and 0 .39 +0.18, respectively. We also present the π0p invariant-mass distribution of the neutrino-induced reactions

Search for y rays above 10^14 eV from Cygnus X-3 during the June and July 1989 radio outbursts

Journal ArticleWe have looked for γ-ray emission above 100 TeV from the binary x-ray source Cygnus X-3 during a period of intense radio emission in the summer of 1989. We find no evidence for excess air showers from the direction of the source and the muon content of air showers from this direction is the same as that of ordinary cosmic rays. The flux of γ rays from Cyguns X-3 with energies exceeding 2.1 X 10^14 eV is <5.5 X 10^-13cm-1 sec -1 (90%C.L.)

Observation of the suppression of the flux of cosmic rays above 4×10^19eV

Journal ArticleThe energy spectrum of cosmic rays above 2.5 x 10^18 eV, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index γ of the particle flux, J∞ E-γ, at energies between 4 x 10^18 eV and 4 x 10^19 eV is 2.69 ± 0.02(stat) ± 0.06(syst), steepening to 4.2 ± 0.4(stat) ± 0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min

An analog light scattering experiment of hexagonal icelike particles. part II: experimental and theoretical results

Journal ArticleThe scattering properties of hexagonal icelike crystals as measured in the analog manner by the experimental apparatus described in Part I are presented. The crystals are made out of sodium fluoride (NaF), which has an index of refraction similar to that of water ice. The experimentally determined light intensities scattered from fixed and integrated random orientations of a NaF hexagonal crystal, oriented to produce a two-dimensional scattering profile, compares favorably to the expectations derived from geometric ray tracing methods. Also, the three-dimensional scattering properties of a simulated NaF Parry column, a NaF crystal aggregate, and a NaF plate with a rough surface are compared to results computed from the geometric ray tracing approach. From these comparisons the Author's conclude that within the experimental measurement uncertainties and to the degree in which the NaF crystal models approach the geometric and optical ideal, the geometric ray tracing approach is an excellent method to determine the single-scattering properties of hexagonal ice crystals of various shapes in the geometric optics domain

An analog light scattering experiment of hexagonal icelike particles. part I: experimental apparatus and test measurements

Journal ArticleAn experimental apparatus to measure the scattering properties of hexagonal icelike particles in the analog manner at the helium neon laser wavelength of 0.633 mm has been designed and built. The instrument consists of an array of 36 highly sensitive and linear photodiode detectors that are positioned to measure the light between the scattering angles of 2.88 and 177.28 in approximately 2.58 increments and at any desired azimuthal angle. This array is calibrated such that the retrieved light signals are corrected to the actual light seen by the detectors to within approximately 6% at all applicable scattering and azimuthal angles. A system of electro-mechanical positioners places the sample at the desired and known position. A glass sphere and a glass fiber configured to scatter light like an infinite cylinder was used to test the operational effectiveness and calibration of the experimental apparatus. The phase functions for the parallel and perpendicular components determined from the experimental results match closely with the results computed from Mie theory