Yiharn Tzeng

Cascade production in heavy-ion collisions at SIS energies

Production of the doubly strange $Ξ$ baryon in heavy-ion collisions at \textrm{SIS} energies is studied in a relativistic transport model that includes perturbatively the strangeness-exchange reactions $\bar{K}Λ\to πΞ$ and $\bar{K}Σ\to πΞ$. Taking the cross sections for these reactions from the predictions of a hadronic model, we find that the $Ξ$ yield is about $10^{-4}$ in central collisions of $% ^{58}$Ni + $^{58}$Ni at $E/A=1.93$ \textrm{GeV}. The $Ξ$ yield is further found to be more sensitive to the magnitude of the cross sections for strangeness-exchange reactions than to the medium effects due to modified kaon properties. We have also made predictions for $Ξ$ production in Au+Au collisions at energies from 1 to 2 GeV/nucleon.