Production of Σ− and Ξ− measured with the DELPHI detector

The production rate of Σ − in Z 0 decays is measured by DELPHI and the result is presented and compared to JETSET. Due to their long decay length, the decay of Σ ± often takes place outside the three-layered microvertex detector, which makes a direct determination of their track parameters possible. A direct measurement of the Ξ − and Ξ + lifetimes and masses is also presented. The production rate − + Ξ + > qq in all hadronic events is measured and compared to the JETSET model as well as the production rate − + Ξ + > bb in bb events.