Confirmation of Exchange-Degeneracy Predictions in the Line-Reversed Reactions: π + p-->K + Y * (1385) and K - p-->π - Y * (1385) at 11.5 GeV/c

We have measured in a single experimental setup the differential cross sections and polarizations of the ${Y}^{*}(1385)$ produced in the two line-reversed reactions ${\ensuremath{\pi}}^{+}p\ensuremath{\rightarrow}{K}^{+}{Y}^{*}(1385)$ (260 eV/\ensuremath{\mu}b) and ${K}^{\ensuremath{-}}p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}{Y}^{*}(1385)$ (180 eV/\ensuremath{\mu}b) at 11.5 GeV/c. We compare these results to ${\ensuremath{\Sigma}}^{+}$ production in the same experiment. The data have been derived from a triggered bubble-chamber experiment using the SLAC Hybrid Facility. We find that both helicity-flip-dominated (${Y}^{*}$) and helicity-nonflip-dominated ($\ensuremath{\Sigma}$) processes are consistent with weak-exchange-degeneracy predictions.