On the reported detection of sub-GeV antiprotons in galactic cosmic rays Academic Article uri icon


  • Buffington et al.1 claim to have detected a p̄/p ratio of 2.2±0.6 × 10−4 at energies between 130 and 320 MeV. This is several orders of magnitude above theoretical predictions2–4 at these lower energies for p̄ fluxes resulting from collisions of primary cosmic rays with the interstellar gas. Measurements at higher energies by Golden et al.5 show a p̄/p ratio of 5.2±1.5 × 10−4, in excess, by a factor of about 3, of the expected values if p̄s are of secondary origin in the standard model of galactic cosmic rays. The reported H̄e/He ratio1 is significantly lower than the reported p̄/p ratio, raising difficulties with some scenarios6 in which the p̄s are primary cosmic rays from anti-galaxies. Kiraly et al.7 suggest black hole evaporation as a p̄ source. I discuss here scenarios in which the reported sub-GeV p̄ excess might be produced as secondaries in high energy collisions. Such production must take place in compact, optically thick sources.

publication date

  • January 1, 1982

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