Pion double charge exchange on medium-mass nuclei

The differential cross sections of $\rm \sp{56}Fe(\pi\sp+,\ \pi\sp-)\sp{56}Ni$ at $\rm \theta\sb{LAB}$ = $5\sp\circ$, T$\sb{\pi}$ = 164 and 293.4 MeV, and at T$\sb{\pi}$ = 230 MeV, $\rm \theta\sb{LAB}$ = $5\sp\circ$ and 14$\sp\circ$, have been measured using the Energetic Pion Channel and Spectrometer (EPICS) at the Clinton P. Anderson Meson Physics Facility in Los Alamos, New Mexico. The differential cross sections of $\rm \sp{60,62,64}Ni(\pi\sp+,\pi\sp-)\sp{60,62,64}Zn$ at T$\sb{\pi}$ = 164 MeV and $\rm \theta\sb{LAB}$ = 5$\sp\circ$, and those of $\rm \sp{76,78,80,82}Se(\pi\sp+,\pi\sp-)\sp{76,78,80,82}Kr$ at T$\pi$ = 293.2 MeV and $\rm \theta\sb{LAB}$ = 5$\sp\circ$, have also been measured using EPICS. The ground states of the residual nuclei, the double isobaric analog states, the analogs of the electric giant dipole resonances, and a number of other excited states of the residual nuclei were populated. The details of these experiments and data analysis are briefly described. The data are presented and compared to a number of known systematics and semi-empirical models. Some microscopic calculations of the cross sections of $\rm \sp{16}O(\pi\sp+,\pi-)\sp{16}Ne(g.s.)$ and of $\rm \sp{12}C(\pi\sp+,\pi-)\sp{12}O(g.s.)$ are done and the results are presented. Evidences for the analog of the giant Gamow-Teller resonance are also presented