RHIC multiplicity distributions and superposition models

TL;DR

This paper analyzes RHIC multiplicity distributions using superposition models, finding simple pp-based models insufficient but proposing wounded quark models as a promising alternative for heavy ion collision data.

Contribution

It introduces the idea that wounded quark models may better describe heavy ion multiplicity distributions than simple superpositions of pp events.

Findings

Simple superposition of pp events disagrees with heavy ion data for dispersion.

Wounded quark models can potentially reconcile pp data with heavy ion multiplicity distributions.

Abstract

The recent PHENIX mid-rapidity measurements of multiplicity distributions for centrality bins are analyzed in the framework of superposition models. A simple superposition of pp events is shown to disagree with the heavy ion data for dispersion as a function of centrality. However, it is suggested that a model describing properly the pp data and based in the "wounded quark" idea may be compatible with the multiplicity data for heavy ion collisions.