SoftPhoton Analysis of PionProton Bremsstrahlung and the Magnetic Moment of DELTA(1232)
Abstract
We have rigorously derived a special twoenergy twoangle amplitude for the pi^ +/ pgamma process near the Delta(1232) resonance. In order to take into account bremsstrahlung emission from an internal Delta line with both charge and the anomalous magnetic moment lambda(lambda_ Delta for the Delta^ {++} and lambda_ Delta^' for the Delta^0), we have applied a radiation decomposition identity to modify Low's standard prescription for constructing a softphoton amplitude. We have also used the special twoenergytwoangle amplitude to calculate all pi^+/ pgamma cross sections which can be compared with the experimental data. Treading lambda as a free parameter in these calculations, the magnetic moments of the Delta, mu_ Delta for the Delta^ {++} and mu_Delta ^' for the Delta ^0, have been extracted from the UCLA data and the SIN data. The average value of mu _Delta determined from the experimental data is 4.35 e/(2m_{p}) (m_{p} is the proton mass), which is in good agreement with the value 4.25 e/(2m_{p}) predicted by a modified SU(6) model. The average value of mu_Delta^' determined from the experimental data is 0.5 e/(2m _{p}), which is in accord with the value predicted by the SU(6) model. Finally, we show that the overall agreement between theory and experiment is excellent if the special twoenergytwoangle amplitude is used in the calculation with the extracted mu_Delta (or mu _Delta^') as an input.
 Publication:

Ph.D. Thesis
 Pub Date:
 1992
 Bibcode:
 1992PhDT.......221L
 Keywords:

 Physics: Nuclear; Physics: Radiation