Pion absorption in heavy nuclei

Abstract

Cross sections have been measured for proton emission following ${\mathrm{\ensuremath{\pi}}}^{+}$ absorption on $^{6}\mathrm{Li}$, $^{12}\mathrm{C}$, $^{27}\mathrm{Al}$, $^{58}\mathrm{Ni}$, $^{118}\mathrm{Sn}$, $^{208}\mathrm{Pb}$, and $^{238}\mathrm{U}$ for pion kinetic energies of 50, 100, 150, and 200 MeV by using a large-solid-angle bismuth germanate detector array. An increasing fraction of transitions to states of large missing energy and with particles other than protons is observed as the energy and mass increase.