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Title:Use of simple-harmonic forces in the non-relativistic quark model
Author(s):Faiman, David
Doctoral Committee Chair(s):Hendry, A.W.
Department / Program:Physics
Subject(s):simple-harmonic forces
non-relativistic quark model
band structure
paraquark harmonic-oscillator shell model
Abstract:Attention is drawn to a possible band structure displayed by the known N* resonances, The observed spectrum is similar to that predicted by a paraquark harmonic-oscillator shell model. "Exact three-body Schroedinger wave functions are used to compute the N~partial decay widths, assuming the pion emission takes place via a one-quark de-excitat~on, . The agreement with experiment is sufficiently good to warrant an investigation of the N* decay widths of all resonances predicted to havem' up to about 2 GeV, and such an investigation is performed. The model is then used to estimate the radiative widths of the observed N* resonances, In the "second resonance region" of pion photoproduction, both the Sll(1550) and D13(1525) resonances (and possibly the Dll(1470), depending on what should be taken as its Nn width) are expected to be important, while in the "third resonance region" F15(1690), Sll (1710) and D13(1990) are expected to have comparable contributions, The mixing angle between the two Sll resonances is determined to be about 350. In inelastic electron scattering ep -> eN*, the S11(155'0) and D13 (1525) resonances are expected to dominate over the Pll(1470). The neutral Pll(1470) radiative width is found to be smaller than the charged width, in contrast to an SU(3) 10 assignment for this resonance. The model is extended to include the strangeness-zero meson resonances, and the root mean square pion radius is found to be larger than that of the nucleon. The principal failures of the model are its inability to predict the correct shape for the nucleon electromagnetic form factors, and both the proton magnetic moment and the pion-nucleon coupling constant are predicted to be 40% larger than the experimental findings.
Issue Date:1969
Genre:Dissertation / Thesis
Rights Information:1969 David Faiman
Date Available in IDEALS:2011-07-13
Identifier in Online Catalog:6072098

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