The "soft ridge" -- is it initial-state geometry or modified jets?

TL;DR

This paper examines whether the 'soft ridge' observed in heavy ion collisions is caused by jet formation or initial-state geometry effects, analyzing evidence for both explanations.

Contribution

It provides a comparative analysis of jet-related and initial-state geometry interpretations for the soft ridge phenomenon.

Findings

Evidence supports both jet formation and initial-state geometry contributions.

The paper discusses how radial flow might influence the soft ridge.

It evaluates the strengths and limitations of each interpretation.

Abstract

An $\eta$-elongated same-side 2D peak ("soft ridge") in minimum-bias angular correlations from heavy ion collisions has been attributed both to jet formation and to initial-state geometry structure coupled to radial flow. We consider evidence for both interpretations.