Spin-parity analysis of the n pi /sup +/ system produced in the reaction pi /sup +/p to pi /sup +/ pi /sup +/n at 16 GeV/c

A spin-parity analysis of the n pi /sup +/ system produced in the reaction pi /sup +/p to pi /sup +/ pi /sup +/n at 16 GeV/c has shown that apart from the mass enhancements associated with the known resonances Delta /sup +/(1238), N*(1520) and N*(1688), there is an enhancement peaked at M(n pi /sup +/) approximately=1.35 GeV, approximately 0.2 GeV wide. For masses below M(n pi /sup +/) approximately=1.35 GeV this enhancement is predominantly due to J/sup P/=1/2/sup -/ states, while above, the J/sup P/=1/2/sup +/ states predominate. The presence of J/sup P/=1/2/sup -/ states indicates the rule Delta P=(-1)/sup Delta J/ is strongly violated in the diffractive process N to N pi , and hence it cannot be considered a specific characteristic of all diffractive processes. (20 refs).