Searching for the Critical Point of QCD: Theoretical Benchmark Calculations

TL;DR

This paper investigates multiplicity fluctuations in high-energy nuclear collisions using UrQMD, providing predictions for experimental measurements and exploring how fluctuations depend on various analysis parameters.

Contribution

It offers a comprehensive theoretical benchmark of multiplicity fluctuations across energies, incorporating detector acceptance and centrality effects.

Findings

Scaled variances increase with energy in central Pb+Pb collisions.

Fluctuations depend on rapidity, transverse momentum, and centrality selection.

Predictions tailored for the NA49 experiment are provided.

Abstract

We present a comprehensive study of event-by-event multiplicity fluctuations in nucleon-nucleon and nucleus-nucleus interactions from AGS/FAIR to RHIC energies within the UrQMD transport approach. The scaled variances of negative, positive, and all charged hadrons are analysed. The scaled variance in central Pb+Pb collisions increases with energy and behaves similar to inelastic p+p interactions. We find a non-trivial dependence of multiplicity fluctuations on the rapidity and transverse momentum interval used for the analysis and on the centrality selection procedure. Quantitative predictions for the NA49 experiment are given, taking into account the acceptance of the detector and the selection procedure of central events.