Reexamination of Cosmic-Ray Composition around 1018 eV from Fly's Eye Data

The cosmic-ray composition around 1018 eV is reexamined using the Chou-Yang model for the simulation of air showers and comparing with Fly's Eye data. This model is quite different from models previously used. Using this model leads to the same conclusion that the primary cosmic-ray composition gets lighter in the region from 3 × 1017 eV to 1019 eV. This conclusion of a changing composition is not sensitive to the choice of model because it results from the measured elongation rate being greater than that predicted for a constant composition by any reasonable model that can account for the measured depths of shower maxima at the Fly's Eye threshold energy. That constraint on elongation rate for a constant composition also implies that the increased rate of energy dissipation that appears in hadron-nucleus interactions near 1014 eV may continue up to the region of 1019 eV.

[1]  Fletcher,et al.  SIBYLL: An event generator for simulation of high energy cosmic ray cascades. , 1994, Physical review. D, Particles and fields.

[2]  Huang,et al.  Evidence for correlated changes in the spectrum and composition of cosmic rays at extremely high energies. , 1993, Physical review letters.

[3]  Mihashi,et al.  Observation of heavy cosmic-ray primaries over the wide energy range from ~100 GeV/particle to ~100 TeV/particle: Is the celebrated "knee" actually so prominent? , 1993, Physical Review D, Particles and fields.

[4]  Dawson,et al.  Cosmic-ray composition around 10(1)8 eV. , 1993, Physical review. D, Particles and fields.

[5]  T. Gaisser.  Hadronic interactions at energies above 1019 eV , 1992 .

[6]  M. J. Menon,et al.  Observation of very high energy cosmic-ray families in emulsion chambers at high mountain altitudes (I) , 1992 .

[7]  J. Grunsfeld,et al.  Energy spectra and composition of primary cosmic rays , 1991 .

[8]  W. Zhu,et al.  Nuclear shadowing in the constituent quark model , 1990 .

[9]  P. Sommers,et al.  Measurements of cosmic-ray air shower development at energies above 10 to the 17th eV , 1990 .

[10]  T. Burnett,et al.  Energy Spectra of Cosmic Rays above 1 TeV per Nucleon , 1990 .

[11]  Li,et al.  Hadronic interactions and primary-cosmic-ray composition at energies around 10(15)-10(16) eV derived from the analysis of high-energy gamma families. , 1988, Physical review. D, Particles and fields.

[12]  G. J. Alner,et al.  The UA5 High-Energy anti-p p Simulation Program , 1986 .

[13]  G. J. Alner,et al.  Scaling of pseudorapidity distributions at c.m. energies up to 0.9 TeV , 1986 .

[14]  Capella,et al.  Koba-Nielsen-Olesen-scaling violations in the dual parton model. , 1985, Physical review. D, Particles and fields.

[15]  Pierre V. Sokolsky,et al.  The Utah Fly's Eye detector , 1985 .

[16]  Chou,et al.  Geometrical model of multiparticle production in hadron-hadron collisions. , 1985, Physical review. D, Particles and fields.

[17]  Yen,et al.  Single-particle momentum distribution at high energies and concept of partition temperature. , 1985, Physical review letters.

[18]  G. Cassiday.  Observatory for Ultra High-Energy Processes: The Fly's Eye , 1985 .

[19]  Y. Mizumoto,et al.  Total Proton Proton Cross-Section at s**(1/2) = 30-TeV , 1984 .

[20]  Y. Mizumoto,et al.  Inelastic p-air cross section at energies between 10/sup 16/ and 10/sup 18/ eV estimated from air-shower experiments , 1983 .

[21]  M. Shibata,et al.  Nuclear interactions and primary cosmic-ray component around 10 15 eV viewed through the cluster analysis of γ-ray families , 1982 .

[22]  M. Shibata.  Breakdown of Feynman Scaling in High-energy Cosmic Ray Interactions , 1981 .

[23]  A. Capella,et al.  Hadron-nucleus interactions and the leading particle effect in a dual-parton model , 1981 .

[24]  A. Watson,et al.  Validity of Scaling to 10 20 eV and High-Energy Cosmic-Ray Composition , 1981 .

[25]  C. Lattes,et al.  Hadronic interactions of high energy cosmic-ray observed by emulsion chambers , 1980 .

[26]  E. Kyriakopoulos.  Infinite multiplets with SU(3) , 1971 .

[27]  R. Glauber,et al.  High-energy scattering of protons by nuclei , 1970 .

[28]  K. Greisen,et al.  Cosmic Ray Showers , 1960 .