Charged Pion Photoproduction on the p-Shell Nuclei at Low Energy and Rescattering Effect of a Pion

Abstract

0. Our results show that the rescattering processes give large effect on the negative pion photoproduc­ tions on 13C and l5N, while they give small effect on the positive pion photoproductions on l2C. This feature strongly depends upon the nuclear structure. ) or Blomqvist-Laget,ZZ) and pion wave function is described by the optical potential of the Kisslinger type Z3 ) or its improved ones. Z4 )-Z7) The sophisti­ cated DWIA calculation in the momentum space was also performed by several groups.Z8)-33) As results, most of the theoretical works succeeded in reproducing the experimental data of spin-flip type on the positive pion production, where the effects of the nuclear core polarization and the meson-exchange current were also investigat­ ed in connection with the magnetic dipole form factors in the electron scattering. 34 ) On the other hand, DWIA cannot explain the experimental data of the negative pion production such as 13C(y, 7(-) 13 N and 15N(y, 7(-) 15 0. These reactions take place between the spin and isospin doublet. The nuclear transition matrix element for these reactions consists of the EO and M1 types, both of which equally contribute to the reactions. By comparing the experimental data with DWIA results, Shoda et al. lO )