Cosmic Ray Antiprotons 5–12 GeV

Secondary antiprotons are a potentially interesting probe of cosmic ray propagation because their production cross section is strongly energy-dependent, increasing by more than two orders of magnitude between 10 and 1000 GeV/c. This is quite unlike the case for fragmentation cross sections of complex nuclei, which are virtually constant with energy. Moreover, the \( \overline p \) flux depends primarily on the environment seen by protons which need not be identical to that probed by other nuclei.