Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions

TL;DR

This study presents the first three-particle coincidence measurements in high-energy nucleus-nucleus collisions, revealing that the ridge component is long-range in pseudorapidity and uncorrelated with the jet-like component and among particles within the ridge.

Contribution

It introduces a novel three-particle coincidence measurement technique to distinguish jet-like and ridge correlations in heavy-ion collisions.

Findings

Ridge particles are uncorrelated in pseudorapidity with the trigger and among themselves.

The ridge production is independent of the jet-like component.

The measurement provides new insights into the nature of long-range correlations in heavy-ion collisions.

Abstract

We report the first three-particle coincidence measurement in pseudorapidity ($\Delta\eta$) between a high transverse momentum ($p_{\perp}$) trigger particle and two lower $p_{\perp}$ associated particles within azimuth $\mid$$\Delta\phi$$\mid$$<$0.7 in $\sqrt{{\it s}_{NN}}$ = 200 GeV $d$+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jet-like component and the ridge (long-range $\Delta\eta$ correlation). The results indicate that the particles from the ridge are uncorrelated in $\Delta\eta$ not only with the trigger particle but also between themselves event-by-event. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jet-like component.