The A dependence of proton yields in the absorption reaction of stopped π− mesons

Experimental results on the yields and spectra of protons produced during the absorption of stopped pions by nuclei are presented. The measurements were performed on the accelerator at the St. Petersburg Nuclear Physics Institute, Russian Academy of Sciences, using a two-arm semiconductor spectrometer of charged particles on a set of nuclei that includes light nuclei 6,7Li, 9Be, 10,11B, and 12C; medium nuclei 28Si, 40Ca, 59Co, and 93Nb; tin isotopes 114,117,120,124Sn; and heavy nuclei 169Tm, 181Ta, and 209Bi. The A dependences of the proton yields and their components are obtained. Some indications of the dominant role of pion absorption on intranuclear pp pairs in the formation of fast protons are presented.