The absorption of π− at rest on complex nuclei

The energy, width and intensity of prompt nuclear γ-rays following capture of π^? at rest by ⁹Be, ¹⁰B, ¹⁶O, ¹⁹F, ³¹P, Ca and ⁹³Nb were measured with a Ge(Li) detector. In most cases it was possible to identify the final nucleus from the energy of the observed γ-ray. Using the measured Doppler broadening of γ-rays from short-lived states, the vector sum momentum distribution of the emitted nucleons was calculated. From the measured γ-ray intensities, isotopic yields were deduced corresponding to the removal of from 1 to 12 nucleons. The average number of removed nucleons changes from 3.0 to 5.5 as the target varies from ¹⁶O to ⁴⁰Ca. A comparison was made with data from both spallation reactions and multi-nucleon pickup reactions.