Statistical properties of non-flow correlations in pp and heavy-ion collisions at RHIC energies

TL;DR

This paper investigates the statistical properties of non-flow correlations in various collision systems at RHIC energies by analyzing the skewness and kurtosis of two-particle cumulant distributions, revealing differences between models and collision types.

Contribution

It provides a detailed analysis of the skewness and kurtosis of two-particle cumulants across different collision systems and models, highlighting the behavior of non-flow correlations at RHIC energies.

Findings

Non-flow correlations produce skewed distributions regardless of the model.

HYDJET++ yields Gaussian distributions at higher $ta$ windows.

Skewness and kurtosis increase with $ta$ in non-QGP models.

Abstract

In this work, we have studied the two-particle cumulant in pp, d-Au, and Au-Au collisions. The two-particle cumulant was treated as an event-by-event distribution, and its skewness and kurtosis were analyzed. The non-flow correlations, like jets and decays, constantly produced a skewed distribution, regardless of the model used. On the contrary, HYDJET++ produced a smooth Gaussian distribution at higher $\eta$ windows in fixed impact parameter collisions. The skewness increased consistently for higher $\eta$ windows in all non-QGP models like PYTHIA, PHOJET, QGSJET, and DPMJET. The kurtosis of the distribution also increased with $\eta$ windows in non-QGP models. The skewness and kurtosis of the distributions produced by HYDJET++ decreased with $\Delta\eta$ and eventually reached zero at higher $\Delta\eta$.