Hydrodynamic approach to the centrality dependence of di-hadron correlations

TL;DR

This paper explains the centrality-dependent features of di-hadron correlations in heavy-ion collisions using a hydrodynamic model that incorporates elliptic flow and peripheral fluctuations, matching experimental data.

Contribution

It introduces a hydrodynamical model combining elliptic flow and peripheral fluctuations to reproduce di-hadron correlation features observed in experiments.

Findings

The model reproduces the evolution from double- to single-peak structures.

Results are in reasonable agreement with PHENIX experimental data.

Highlights the role of peripheral fluctuations in correlation structures.

Abstract

Measurements of di-hadron azimuthal correlations at different centralities for Au+Au collisions at 200 AGeV were reported by the PHENIX Collaboration. The data were presented for different ranges of transverse momentum. In particular, it was observed that the away-side correlation evolves from double- to a single-peak structure when the centrality decreases. In this work, we show that these features naturally appear as due to an interplay between the centrality-dependent smooth background elliptic flow and the one produced by event-by-event fluctuating peripheral tubes. To compare with the PHENIX data, we also carry out numerical simulations by using a hydrodynamical code NeXSPheRIO, and calculate the correlations by both cumulant and the ZYAM method employed by PHENIX Collaboration. It is shown that our results are in reasonable agreement with the data. A brief discussion on the physical content of the present model and its difference from other viewpoint is also presented.