(Multiple) Hard Parton Interactions in Heavy-Ion Collisions

TL;DR

This paper reviews the role of multiple hard parton interactions in high-energy proton-proton and nucleus-nucleus collisions, emphasizing their impact on particle multiplicity and jet background understanding at RHIC.

Contribution

It provides an overview of experimental results on high-pT particle production and discusses the centrality dependence of multiplicity in heavy-ion collisions in the context of multiple partonic interactions.

Findings

Multiple hard interactions significantly influence particle multiplicity in heavy-ion collisions.

They are crucial for understanding the underlying event in jet reconstruction.

Experimental data at RHIC supports the importance of these interactions.

Abstract

Multiple hard interactions of partons in the same p+p(\bar p) collision are a useful concept in the description of these collisions at collider energies. In particular, they play a crucial role for the understanding of the background (the so-called underlying event) in the reconstruction of jets. In nucleus-nucleus collisions multiple hard parton interactions and the corresponding production of mini-jets are expected to contribute significantly to the total particle multiplicity. In this article a brief overview of results on particle production at high-pT in proton-proton and nucleus-nucleus at RHIC will be given. Moreover, the observed centrality dependence of the charged particle multiplicity in Au+Au collisions will be discussed in light of multiple partonic interactions.