Correlations of azimuthal anisotropy harmonics in pp, pPb and PbPb collisions at the LHC

The first measurements of anisotropy harmonics ($v_n$, $n=2-4$) in $\text{pPb}$ collisions at $\sqrt{s_{_{NN}}} = 8.16~\mathrm{TeV}$ is presented. In addition, measurements of event-by-event correlations of different $v_n$ in $\text{pp}$ at $\sqrt{s} = 13~\mathrm{TeV}$, $\text{pPb}$ at $\sqrt{s_{_{NN}}} = 5.02$ and $8.16~\mathrm{TeV}$ and $\text{PbPb}$ at $\sqrt{s_{_{NN}}} = 5.02~\mathrm{TeV}$ collision systems at the LHC are explored. New results of the $v_n$ harmonics in $8.16~\mathrm{TeV}$ $\text{pPb}$ collisions are extracted via long-range ($|\Delta\eta|>2$) two-particle correlations as a function of event multiplicity. The current measurement is reaching a very-high-multiplicity region beyond that achieved in $5.02~\mathrm{TeV}$ $\text{pPb}$ data collected in 2013. Event-by-event correlations among $v_2$, $v_3$ and $v_4$ harmonics are measured using the four-particle symmetric cumulant method in $\text{pp}$ and $\text{pPb}$, and compared to the large system of $\text{PbPb}$ collisions. For high-multiplicity (more than 100 tracks) $\text{pp}$ and $\text{pPb}$ events, the $v_2$ harmonic is found to have a negative correlation with the $v_3$ harmonic, while the $v_2$ and $v_4$ harmonics are positively correlated. Normalized by the two-particle $v_n$ harmonics, the correlation coefficients of $v_2$ and $v_3$ harmonics are quantitatively similar for $\text{pPb}$ and $\text{PbPb}$ data, while a strong system size dependence is observed for correlations of $v_2$ and $v_4$ harmonics. These new data provide important insights to the origin of collectivity observed in small collision systems.