Two-nucleon production of hyperons in an S = (minus)1 dibaryon search

摘要

The double-charge-exchange reaction (sup 3)He(K(sup (minus)), (pi)(sup +))Xn was studied at p(sub K)- = 870 MeV/c. In the missing mass range below the sigma-nucleon production threshold (3075 MeV/c(sup 2)) events were detected and attributed to the two-nucleon reaction pp(K(sup (minus)), (pi)(sup +))(Lambda)n. This reaction and mass range is supposed to be a fertile field for a search for the I = 1/2, L = 1 ((sup 1)P(sub 1)) spin-singlet dibaryon suggested as the lowest mass S = (minus)1 dibaryon of bag model predictions. We find no need to invoke such an object to account for the observed events below (Sigma) production threshold.