The photoproduction of neutral pions from hydrogen

Citation

Oakley, David Charles (1955) The photoproduction of neutral pions from hydrogen. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-01132004-105847

Abstract

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The photoproduction of neutral pions from hydrogen has been studied by counting the recoil protons with a magnetic spectrometer and scintillation counters. The process was studied between photon energies of 260 and 450 MEV and between center of mass pion angles of 70[degrees] and 153[degrees]. The excitation functions show a resonance type shape with maxima at about 320 MEV. Angular distributions are approximately [...] plus a small constant between zero and one third. There is indication of little asymmetry in the angular distributions. The maximum cross section at 90[degrees] in the center of mass is [...]/steradian for 320 MEV photons. The total cross section divided by the square of the center of mass photon wave length has a maximum at 340 MEV. This quantity drops by about a factor of two at 450 MEV. These results are consistent with magnetic dipole and electric quadrupole absorption leading to a resonant state of the pion-nucleon system of angular momentum j = 3/2 and isotopic spin T = 3/2.

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