Two-particle cumulant distribution: a simulation study of higher moments

TL;DR

This study uses PYTHIA8/Angantyr simulations to analyze two-particle correlations in d-Au collisions, focusing on higher moments like skewness and kurtosis to differentiate flow from non-flow effects.

Contribution

It introduces the analysis of higher moments of two-particle cumulant distributions to distinguish true flow from non-flow correlations in heavy-ion collisions.

Findings

Non-flow correlations deviate from Gaussian, showing high skewness and kurtosis.

True elliptic flow distributions are approximately Gaussian with lower skewness and kurtosis.

Skewness and kurtosis of flow distributions can help separate flow from non-flow effects.

Abstract

In this work, we have shown the two-particle correlations of charged hadrons in d-Au collisions at 200 GeV in PYTHIA8/Angantyr simulations. These correlations were studied at different multiplicities and pseudorapidity intervals. The two-particle correlations arise due to color reconnections, resonance decays, jet correlations, and hadronic rescattering. These correlations are inversely proportional to multiplicity but remain unaffected for larger pseudorapidity windows. We treated these correlations as distributions and calculated their skewness and kurtosis. The non-flow distributions deviate greatly from a Gaussian distribution and have high skewness and kurtosis. The ``true" elliptic flow distributions resemble Gaussian distributions; they have significantly lower skewness and kurtosis. We suggest that if the two-particle cumulant flow is treated as an event-by-event distribution, its skewness and kurtosis can be instrumental in distinguishing true flow and non-flow.