Energy and system dependence of high-$p_T$ triggered two-particle near-side correlations

TL;DR

This paper investigates the energy and system dependence of near-side correlations in high-$p_T$ triggered events, decomposing them into Jet and Ridge components across various collision systems and energies, and compares the Jet to PYTHIA simulations.

Contribution

It provides new measurements of Jet and Ridge yields in different collision systems and energies, and analyzes their dependence to inform models of Ridge production.

Findings

PYTHIA describes the Jet component up to a scaling factor.

Ridge yield varies with collision energy and system.

Data helps distinguish models for Ridge production.

Abstract

Previous studies have indicated that the near-side peak of high-$p_T$ triggered correlations can be decomposed into two parts, the \textit{Jet} and the \textit{Ridge}. We present data on the yield per trigger of the \textit{Jet} and the \textit{Ridge} from $d+Au$, $Cu+Cu$ and $Au+Au$ collisions at $\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV and compare data on the \textit{Jet} to PYTHIA 8.1 simulations for $p+p$. PYTHIA describes the \textit{Jet} component up to a scaling factor, meaning that PYTHIA can provide a better understanding of the \textit{Ridge} by giving insight into the effects of the kinematic cuts. We present collision energy and system dependence of the \textit{Ridge} yield, which should help distinguish models for the production mechanism of the \textit{Ridge}.