Disappearance of the Mach Cone in heavy ion collisions

TL;DR

This paper analyzes di-hadron correlations in heavy ion collisions, showing that low momentum jets do not form Mach cones but are subtly modified by the medium, challenging previous interpretations.

Contribution

It introduces advanced background subtraction methods enabling more precise measurements and clarifies the absence of Mach cone signatures in jet-medium interactions.

Findings

Low momentum jets do not equilibrate with the medium.

Interactions cause subtle increases in jet widths and fragmentation.

The away-side shape is inconsistent with a Mach cone.

Abstract

We present an analysis of di-hadron correlations using recently developed methods for background subtraction which allow for higher precision measurements with fewer assumptions about the background. These studies indicate that low momentum jets interacting with the medium do not equilibrate with the medium, but rather that interactions with the medium lead to more subtle increases in their widths and fragmentation functions, consistent with observations from studies of higher momentum fully reconstructed jets. The away-side shape is not consistent with a Mach cone.