Mass dependence of pion single-charge exchange to the isobaric analog state at 20 MeV

F. Irom; H. W. Baer; A. G. Bergmann; J. D. Bowman; P. Heusi; D. H. Fitzgerald; C. J. Seftor; M. E. Sadler; J. N. Knudson; W. J. Briscoe; P. W. F. Alons; E. Piasetzky; S. H. Rokni

doi:10.1103/PhysRevC.36.1453

Mass dependence of pion single-charge exchange to the isobaric analog state at 20 MeV

F. Irom, H. W. Baer, A. G. Bergmann, J. D. Bowman, P. Heusi, D. H. Fitzgerald, C. J. Seftor, M. E. Sadler, J. N. Knudson, W. J. Briscoe, P. W. F. Alons, E. Piasetzky, and S. H. Rokni

Phys. Rev. C 36, 1453 – Published 1 October 1987

Abstract

Forward-angle differential cross sections for pion single-charge exchange to the isobaric-analog state were measured for ${}^{7}{Li}$ , ${}^{14}C$ , ${}^{15}N$ , and ${}^{120}{Sn}$ at 20 MeV incident beam energy. Back-angle differential cross sections for ${}^{7}{Li}$ were also measured. The shape of the angular distributions for light nuclei is featureless. The cross section for ${}^{7}{Li}$ at 180° is as large as the cross section at 0°. The A dependence of the 0° cross section can be expressed as g(N-Z) $A^{α}$ (with g=534 and α=0.73±0.09), leading to the conclusion that the nuclear medium is neither strongly absorbing nor fully transparent. The data are compared with optical-model calculations.