Production and Annihilation of Antiprotons

Abstract

If protons and neutrons are Dirac particles, as one usually assumes, the corresponding antiparticles should ex­ist, but these have never been observed. The coupling of nucleons with the meson field offers processes by which these particles could be created in energetic collisions be­tween nucleons and mesons or other nucleons. In this thesis the pseudoscalar meson theory is used to calculate cross-sec­tions for the production of antiprotons in such collision processes. These are applied to estimate the numbers of antiprotons to be expected from the interaction of cosmic­ ray particles with the nucleons of the atmosphere. It is found that meson production is about 60 times more frequent than antinucleon production for the complete primary cosmic­ ray spectrum, but that antinucleon production is of compar­able probability with meson production for energies greater than about 1011 e.v. Cross-sections are also calculated for the annihilation of antiprotons in collisions with protons and neutrons, with emission of mesons.