$\Xi^{-}$ and $\bar{\Xi}^{+}$ production in Pb+Pb collisions at 40 A GeV at CERN SPS

First results on the production of $\Xi^{-}$ and $\bar{\Xi}^{+}$ hyperons in Pb+Pb interactions at 40 AGeV are presented. The $\bar{\Xi}^{+}/\Xi^{-}$ ratio at midrapidity is studied as a function of collision centrality. The ratio shows no significant centrality dependence; it ranges from 0.07 to 0.15. The $\bar{\Xi}^{+}/\Xi^{-}$ ratio for central Pb+Pb collisions increases strongly with the collision energy.