Dispersion theory of proton Compton scattering in the first and second resonance regions
1997; American Institute of Physics; Volume: 55; Issue: 1 Linguagem: Inglês
10.1103/physrevc.55.359
ISSN1538-4497
AutoresA. I. L’vov, V.A. Petrun'kin, M. Schumacher,
Tópico(s)Radiation Detection and Scintillator Technologies
ResumoDispersion theory of proton Compton scattering is extended to energies up to \ensuremath{\sim}1 GeV where excitations of higher resonances and nonresonance double-pion photoproduction become important photoabsorption mechanisms. To saturate s-channel dispersion relations, the VPI partial-wave analysis of single-pion photoproduction and resonance photocouplings is used. Models for double-pion photoproduction and dispersion asymptotic contributions are constructed. The latter are mainly given by ${\mathrm{\ensuremath{\pi}}}^{0}$ and \ensuremath{\sigma}(600) exchanges. Being used in dispersion calculations, they result in a reasonable agreement with all available data on both differential cross sections and polarization observables in Compton scattering. Some unsolved problems are outlined.
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