Production and Annihilation of Antiprotons

Citation

Helstrom, Carl Wilhelm (1951) Production and Annihilation of Antiprotons. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RCCV-Z308. https://resolver.caltech.edu/CaltechTHESIS:10132017-101145132

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.

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