# Non-flow effects in three-particle mixed-harmonic azimuthal correlations in small collision systems

## TL;DR

This paper investigates the impact of non-flow correlations on three-particle mixed-harmonic azimuthal correlations in small collision systems, using models to compare with experimental data and assess suppression techniques.

## Contribution

It provides the first detailed estimation of non-flow effects on three-particle correlators in small systems using PYTHIA and HIJING models, and evaluates the effectiveness of subevent methods.

## Key findings

- Non-flow effects from jets are largely suppressed in p+Pb collisions with subevent methods.
- Non-flow effects may still be significant in pp collisions depending on the method used.
- The study helps clarify the role of non-flow correlations in interpreting collective phenomena.

## Abstract

The Multi-particle technique has been used to unravel the nature of the long-range collectivity in small collision systems. A large three-particle mixed-harmonic correlation signal was recently observed by the ATLAS Collaboration, but the role of non-flow correlations is not yet studied. We estimate the influence of non-flow correlations to the three-particle correlators in $pp$ and $p$+Pb collisions using PYTHIA and HIJING models, and compare with the ATLAS results. The large non-flow effects from the jet and dijet production is found to be largely suppressed in $p$+Pb collisions using the subevent cumulant method by calculating the azimuthal correlation between two or more longitudinal pseudorapidity ranges. Depending on the experimental subevent method, however, the non-flow effects may still be significant in $pp$ collisions.