Before revision: They predicted that cosmic rays with energies over the threshold energy of would interact with cosmic microwave background photons , relatively blueshifted by the speed of the cosmic rays, to produce pions through the resonance, or Pions produced in this manner proceed to decay in the standard pion channels — ultimately to photons for neutral pions, and photons, positrons, and various neutrinos for positive pions.
After revision: They predicted that cosmic rays with energies over the threshold energy of would interact with cosmic microwave background photons , relatively blueshifted by the speed of the cosmic rays, to produce pions through the resonance, or Pions produced in this manner proceed to decay in the standard pion channels – ultimately to photons for neutral pions and photons, positrons, and various neutrinos for positive pions.