Energy and System-size Dependence of Two-particle Azimuthal Correlations of High-pT Charged Hadrons at the CERN SPS

TL;DR

This study investigates how two-particle azimuthal correlations of high-pT charged hadrons vary with energy and system size in heavy-ion collisions at CERN SPS, aiming to identify the primary sources of these correlations.

Contribution

It provides the first systematic energy and system-size scan of two-particle azimuthal correlations at SPS energies, including comparisons with UrQMD simulations.

Findings

Correlations depend on system size and collision energy.

Results suggest non-negligible non-flow contributions at SPS energies.

Comparison with UrQMD offers insights into the underlying physics.

Abstract

Angular correlations of high-pT hadrons can serve as a probe of interactions of partons with the dense medium produced in high-energy heavy-ion collisions but other sources of such correlations exist which can be non-negligible SPS energies. In an attempt to determine the primary source, NA49 has performed an energy and system-size scan of two-particle azimuthal correlations in central Pb+Pb, Si+Si and p+p collisions at 158A GeV, as well as central Pb+Pb collisions at 20A, 30A, 40A and 80A GeV. Moreover, results at 158A GeV have been compared to UrQMD simulations.