Charge exchange of 2. 9-GeV/c. pi. /sup +/ mesons on carbon and xenon nuclei

A study is made of the charge exchange of ..pi../sup +/ mesons on carbon and xenon nuclei, ..pi../sup +/+A..-->..p+..pi../sup 0/+A', at a momentum 2.9 GeV/c. Among the events of this type there are approximately identical numbers of events with and without visible excitation of the nucleus. A detailed discussion is given of events without visible nuclear excitation. The distributions in the ..pi../sup 0/-meson energy, the mass of the p..pi../sup 0/ system, the target mass, and the ..pi../sup 0/-meson missing mass agree with the calculated distributions for interaction with a free nucleon with the condition that on the average an energy of approx. 70 MeV is released in the reaction. Events in which the nucleus has momentum < or = 150 MeV/c correspond to the criteria of the pole diagram and are the result of interaction of the ..pi../sup +/ meson with a single weakly bound neutron of the nucleus. The ratio of the number of events of the reaction indicated above and the similar reaction in which the eta (2..gamma..) meson is formed is found to be 4.9 +- 0.9.