Glasma flux tubes vs minimum-bias jets in 2D angular correlations on $\eta$ and $\phi$

TL;DR

This paper critically examines the origin of the elongated same-side peak in heavy ion collision correlations, contrasting Glasma flux tube models with perturbative QCD jet predictions, and finds inconsistencies with experimental data.

Contribution

The paper provides a detailed comparison between Glasma flux tube models and perturbative QCD predictions, challenging the saturation-scale explanation for the elongated correlation peak.

Findings

Glasma flux tube model is inconsistent with measured spectra.

Perturbative QCD better explains jet-related correlations.

The 'soft ridge' is more compatible with jet correlations than flux tube interactions.

Abstract

Angular correlations measured in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) include a same-side (SS) 2D peak which is strongly elongated on pseudorapidity $\eta$ in more-central \auau collisions. The elongated peak has been referred to as a ``soft ridge.'' The SS peak is consistent with expected jet correlations in peripheral \aa and p-p collisions. A saturation-scale argument has been proposed to explain the origin of the elongated SS peak in terms of correlations from Glasma flux tubes interacting with radial flow. In this analysis we review the details of the proposed argument in comparison to perturbative QCD predictions of jet yields and correlations. We find that the proposal is inconsistent with several features of measured spectra and correlations.