The reactions K/sup -/p to pi /sup -or+/ Sigma /sup +or-/(1385) at 42 GeV/c

The total and differential cross sections are presented. Amplitude analyses are performed and the complete sigma /sup +or-/(1385) helicity spin density matrices are extracted. The results are compared with the predictions of the additive quark model and exchange degeneracy. A substantial cross section is observed for the reaction K /sup -/p to pi /sup +/ Sigma /sup -/(1385) in the forward direction, which implies exotic meson quantum numbers in the t-channel. One possible interpretation of this process provides an explanation for the small but significant violations of the additive quark model predictions observed in the reaction K/sup -/p to pi /sup -/ Sigma /sup +/(1385) at low four-momentum transfer. In the backward direction unnatural parity exchange is shown to give a larger contribution to K /sup -/p to Sigma /sup -/(1385) pi /sup +/ than natural parity exchange. (25 refs).