Double charge exchange of 2. 9-GeV/c. pi. /sup +/ mesons

Results are presented of a study of double charge exchange of 2.9-GeV/c ..pi../sup +/ mesons in a mixture of carbon and xenon nuclei. The cross sections per average mixture nucleus are obtained for double charge exchange with and without production of ..pi../sup 0/ mesons. The momentum and angular distributions of ..pi../sup -/ mesons and protons are given, as well as data on the proton multiplicities. An excess of low-energy ..pi../sup -/ mesons is observed and cannot be explained by the existing double-charge-exchange models.