Observation of correlated azimuthal anisotropy Fourier harmonics in pp and pPb collisions at the LHC

TL;DR

This paper reports the measurement of azimuthal anisotropy Fourier coefficients in pp, pPb, and PbPb collisions at the LHC, revealing correlations that suggest a common origin of collective behavior across these systems.

Contribution

First-time measurement of $v_n$ correlations in pp and pPb collisions, providing new insights into the collective phenomena in small and large collision systems.

Findings

Positive correlation of $v_2$ and $v_4$ across all systems.

Anticorrelation of $v_2$ and $v_3$ in high multiplicity pPb collisions.

Results support a common origin of collectivity in pPb and PbPb collisions.

Abstract

The azimuthal anisotropy Fourier coefficients ($v_n$) in 8.16 TeV pPb data are extracted via long-range two-particle correlations as a function of event multiplicity and compared to corresponding results in pp and PbPb collisions. Using a four-particle cumulant technique, $v_n$ correlations are measured for the first time in pp and pPb collisions. The $v_2$ and $v_4$ coefficients are found to be positively correlated in all collision systems. For high multiplicity pPb collisions an anticorrelation of $v_2$ and $v_3$ is observed, with a similar correlation strength as in PbPb data at the same multiplicity. The new correlation results strengthen the case for a common origin of the collectivity seen in pPb and PbPb collisions in the measured multiplicity range.