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Photoproduction of Positive Pions from Hydrogen at Small Angles at Energies 700 to 1025 Mev


Boyden, James Harrison (1961) Photoproduction of Positive Pions from Hydrogen at Small Angles at Energies 700 to 1025 Mev. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DN4T-5P09.


NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Measurements of the cross section for photoproduction of [...] mesons from hydrogen have been extended to angles as small as 5[...] in the c. m. system, using a magnetic spectrometer. At a photon energy of 1025 Mev, the cross section decreases as the angle changes from 5[degrees] to 13[degrees], reaching a minimum before increasing again to the maximum near 40[degrees] which has been previously observed (5). Less extensive measurements at energies 700, 800, 900, and 960 Mev all show a similar rapid decrease with angle in the angular range less than 15[degrees] c.m., although below 960 Mev no actual minimum is observed. These effects at small angles arise presumably from the "retardation term", or "meson current" term and its interference with other contributions to the photoproduction amplitude. It is interesting that a minimum near 15[degrees] is characteristic of the pure Born approximation (retardation term plus "S-wave"). Values of the 0[degree] cross section that are much more accurate than previous estimates have been obtained. An attempt has been made to extract a value of the pion-nucleon coupling constant by an extrapolation into the region cos [...]. Using the best set of data, the value obtained was [...].

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Physics)
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Walker, Robert Lee
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1961
Record Number:CaltechETD:etd-05062005-111053
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1650
Deposited By: Imported from ETD-db
Deposited On:09 May 2005
Last Modified:10 Nov 2023 23:36

Thesis Files

PDF (Boyden_jh_1961.pdf) - Final Version
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