arXiv:nucl-th/9612055·v1·Nuclear Theory
Pion Absorption Cross Section for ^2H and ^3He in the Delta-Isobar Region: A Phenomenological Connection
H. Kamada (1) · M. P. Locher (1) · T.-S. H. Lee (2) · J. Golak (3) · V. E. Markushin (1) · W. Glöckle (4) · H. Witala (3) ((1) Paul Scherrer Institut, (2) Argonne National Laboratory, (3) Institute of Physics, Jagellonian University, Cracow, (4) Institut für Theor. Physik II, Ruhr Univ. Bochum)
Abstract
The absorption of \pi^+ on ^3He in the -region is evaluated with exact inclusion of the final state interaction among the three emerging protons. The absorption is described by a vertex and a transition t-matrix which are calculated from a phenomenological model for NN and \pi d reactions. In a calculation where the initial pion scattering effects are neglected, the predicted peaks of the pion absorption cross sections for ^2H and ^3He lie too high in energy in relation to the data. The effect of the final state three-nucleon interaction turns out to be too small for changing the magnitude and shifting the peak position of the total absorption cross section for ^3He. We demonstrate that the adjustment of the peak position for the deuteron cross section by small modifications of the -parameters, automatically leads to the correct peak position in ^3He.
Comments: 12 pages, REVTeX, 10 PostScript figures, submitted to Phys. Rev. C