Secondary Antiprotons in Galactic Cosmic Radiation

Calculations are presented of the production of secondary antiprotons due to inelastic collisions of high-energy primary cosmic rays with interstellar gas nuclei. Cosmic-ray diffusion theory is assumed to apply in the steady-state approximation, with a constant average beam intensity taken over space. The cosmic-ray energy spectrum, production thresholds, cosmic-ray and target abundances and densities, and production and annihilation cross sections are examined and utilized. The results give a very approximate energy spectrum for the antiproton flux. Astrophysical ramifications of this collision source of antiprotons are discussed in light of the dominance of leakage over annihilation as a mechanism of antiproton loss.