The Ratio of Negative to Positive Pion Photoproduction from Deuterium by Photons with Energies between 500 and 1000 Mev

Citation

Neugebauer, Gerry (1960) The Ratio of Negative to Positive Pion Photoproduction from Deuterium by Photons with Energies between 500 and 1000 Mev. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/9S38-5H74. https://resolver.caltech.edu/CaltechETD:etd-06282006-102946

Abstract

The ratio of the yields of negative to positive pions photoproduced in deuterium has been obtained at six photon energies between 500 and 1000 Mev and at seven angles between 20° and 160° in the center of mementum system of the photon and the target nucleon. Pions were selected with a magnetic spectrometer and identified using momentum and specific ionization in a scintillation counter telescope. The spectator model of the deuteron was used to identify the photon energy. The statistical errors assigned to the ratio range between five and fifteen percent. The results of the present experiment join smoothly with the low energy pi-/pi+ ratios obtained by Sands et al. At high energies the pi-/pi+ ratio varies from 0.4 at forward angles to 2.8 at backwards angles. The cross-sections for pi- photoproduction from neutrons, derived from the pi-/pi+ ratio and the Caltech photoproduction data, are also presented. A peak in the pi- total cross-section occurs at an energy 25-50 Mev below the energy of the second resonace peak in pi+ photoproduction. A phenomenological analysis has been attempted, but no definite conclusions have been reached.

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