The yield for the multi-strange Ξ− hyperon has been measured in 6 AGeV
Au+Au collisions via reconstruction of its decay products π− and
Λ, the latter also being reconstructed from its daughter tracks of
π− and p. The measurement is rather close to the threshold for Ξ−
production and therefore provides an important test of model predictions. The
measured yield for Ξ− and Λ are compared for several
centralities. In central collisions the Ξ− yield is found to be in
excellent agreement with statistical and transport model predictions,
suggesting that multi-strange hadron production approaches chemical equilibrium
in high baryon density nuclear matter.Comment: Submitted to PR