Evidence for correlated changes in the spectrum and composition of cosmic rays at extremely high energies

Journal Article · Mon Nov 22 00:00:00 EST 1993 · Physical Review Letters; (United States)

DOI:https://doi.org/10.1103/PhysRevLett.71.3401· OSTI ID:5434409

Bird, D J; Corbato, S C; Dai, H Y; Dawson, B R; Elbert, J W; Gaisser, T K; Green, K D; Huang, M A; Kieda, D B; Ko, S; Larsen, C G; Loh, E C; Luo, M; Salamon, M H; Smith, D; Sokolsky, P; Sommers, P; Stanev, T; Tang, J K.K.; Thomas, S B ; Tilav, S ^[1]

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1. Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States) Department of Physics and Mathematical Physics, University of Adelaide, Adelaide, South Australia 5005 (Australia) High Energy Astrophysics Institute, Department of Physics, University of Utah, Salt Lake City, Utah 84112 (United States) Bartol Research Institute, University of Delaware, Newark, Delaware 19716 (United States)

The Utah Fly's Eye detector has revealed a change in the cosmic ray composition which is correlated with structure in the all-particle energy spectrum. The data can be fitted by a simple model of a steep power law spectrum of heavy nuclei which is overtaken at high energies by a flatter spectrum of protons. The transition occurs near 10[sup 18.5] eV. Anisotropy is not detected, so the high-rigidity particles above the transition energy do not originate in the disk of the Galaxy. An outstanding event of 3[times]10[sup 20] eV implies that the highest energy particles originate in the contemporary era of the Universe.

• DOE Contract Number: FG02-91ER40677
• OSTI ID: 5434409
• Journal Information: Physical Review Letters; (United States), Vol. 71:21; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RAY FLUX
CHEMICAL COMPOSITION
ENERGY SPECTRA
ANISOTROPY
EXTREME ULTRAVIOLET SPECTRA
HEAVY NUCLEI
PROTONS
UNIVERSE
BARYONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
NUCLEI
NUCLEONS
RADIATION FLUX
SPECTRA
ULTRAVIOLET SPECTRA
661310* - Relativity & Gravitation- (1992-)