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 6,7 Li, 9 Be, 10,11 B, and 12 C; medium nuclei 28 Si, 40 Ca, 59 Co, and 93 Nb; tin isotopes 114,117,120,124 Sn; and heavy nuclei 169 Tm, 181 Ta, and 209 Bi. 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.