Studying re-scattering effect in heavy-ion collision through $K^{\ast }$ Production

Abstract

We have studied the $K^{\ast }$ production within A Multi-Phase Transport model (AMPT) for Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV to understand the hadronic re-scattering effect on the measured yields of the resonance. The hadronic re-scattering of the $K^{\ast }$ decay daughter particles ($\pi$ and K) will alter their momentum distribution thereby making it difficult to reconstruct the $K^{\ast }$ signal through the invariant mass method. An increased hadronic re-scattering effect thus leads to a decrease in the reconstructed yield of $K^{\ast }$ in heavy-ion collisions. Through this simulation study we argue that a decrease in $K^{\ast }$/K ratio with increase in collision centrality necessarily reflects the hadronic re-scattering effect. Since the re-scattering occurs in the hadronic phase and $K^{\ast }$ has a lifetime of 4 fm/c, we present a toy model based discussion on using measured $K^{\ast }$/K to put a lower limit on the hadronic phase lifetime in high energy nuclear collisions.

Comments: 9 pages, 5 figures, accepted for publication in IJMPE