Resonance Production in Heavy Ion Collisions

Abstract

The resonance production of $Δ$, K(892), $Σ$(1385), $Λ$(1520) and $ϕ$ from elementary p+p and Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200 GeV from the STAR experiment at RHIC is presented. Yields and spectra are discussed in terms of chemical and thermal freeze-out conditions. Thermal models do not describe sufficiently the yields of the resonance production in central Au+Au collisions. The approach which includes pseudo-elastic and elastic hadronic interactions after chemical freeze-out until thermal freeze-out suggests a time span of $Δτ>$5 fm/c.