Constituent Quark Scaling of Strangeness Enhancement in Heavy-Ion Collisions

TL;DR

This paper demonstrates that strangeness enhancement in heavy-ion collisions scales with the number of constituent quarks at RHIC energies, indicating partonic effects, while SPS data show deviations suggesting mixed phases.

Contribution

It introduces a constituent quark scaling approach to analyze strangeness enhancement, revealing partonic influences at RHIC energies and mixed phases at SPS energies.

Findings

N_{N-part}-normalized enhancement increases with centrality.

N_{q-part}-normalized enhancement shows strangeness-independent scaling at RHIC.

Scaling breaks down at SPS energies, indicating different underlying physics.

Abstract

In the frame work of a nuclear overlap model, we estimate the number of nucleon and quark participants in proton-proton, proton-nucleus and nucleus-nucleus collisions. We observe the number of nucleon ($N_{N-part}$)-normalized enhancement of multi-strange particles which show a monotonic increase with centrality, turns out to be a centrality independent scaling behavior when normalized to number of constituent quarks participating in the collision ($N_{q-part}$). In addition, we observe that the $N_{q-part}$-normalized enhancement, when further normalized to the strangeness content, shows a strangeness independent scaling behavior. This holds good at top RHIC energy. However, the corresponding SPS data show a weak $N_{q-part}$-scaling with strangeness scaling being violated at top SPS energy. This scaling at RHIC indicates that the partonic degrees of freedom playing an important role in the production of multi-strange particles. Top SPS energy, in view of the above observations, shows a co-existence of hadronic and partonic phases. We give a comparison of data with HIJING, AMPT and UrQMD models to understand the particle production dynamics at different energies.