Abstract
For a description of elastic and inelastic scattering exciting resonances optical potentials and transition potentials were derived by folding nucleon and nucleus mass densities with a variable range effective interaction. For elastic scattering in forward direction, a reasonable description of essentially all data has been obtained from low energies up to the GeV region. Also, scattering from and is quite well described with potentials, which indicate that the used folding method is a valid approach for the systems in question. The strong energy dependence of the deduced potentials can be accounted for by a sum of scalar and vector meson-exchange potentials and a soft Pomeron-exchange contribution. The scalar meson-exchange potential falls off rapidly with energy and has a large radius in agreement with theoretical predictions. Consistent with the flavor SU(3) quark model, the vector-meson coupling is rather weak in the central potential, but is strong in the spin-orbit potential, for which a soft Pomeron contribution is negligible. The differences between the deduced and nucleon-nucleon potentials are understood; further, an excellent description of the energy dependence of the s-wave amplitudes is obtained in the folding model framework. Distorted wave Born approximation calculations for inelastic scattering show a t-dependence of the cross section consistent with empirical form factors. Absolute yields for excitation of the resonances and were calculated, using resonance shapes from scattering. A quantitative description of the data at is obtained using fluid-dynamical transition densities and strengths exhausting large fractions of scalar energy weighted sum rules. The rather pure scalar (non-spin-isospin-flip) character of these excitations and the observed cross sections are in severe conflict with the constituent quark model. Finally, a prediction is made for scattering at an incident energy of which yields strongly increased cross sections for excitations.
- Received 10 July 2002
DOI:https://doi.org/10.1103/PhysRevC.67.064001
©2003 American Physical Society