Speaker
Description
The azimuthal anisotropies observed in small systems can originate from the final state response to the initial geometry as well as from initial momentum anisotropies. Recently it has been proposed that the correlation between the flow coefficient $v_{2}^2$ and the mean $p_\mathrm{T}$ carries information on the origin of flow in small collision systems by showing a characteristic sign change at very low multiplicity. However, this sign change exists in PYTHIA8 events as a result of nonflow effects. To reduce the nonflow dependence , a new correlator that correlates multiparticle cumulants and mean $p_\mathrm{T}$ is suggested. In this talk, we present results for this correlator using two and four particle correlations in pp, pPb and peripheral PbPb collisions. We also report our high precision measurements of $v_{2}$ using four-, six-, and eight-particle correlations, together with $v_{3}$ from four particle correlations, in both pPb and peripheral PbPb collisions. The ratios between $v_{n}$ harmonics involving different numbers of particles are compared to model calculations to study the fluctuation-driven initial state anisotropies. The results provide insights to the origin of flow in small collision systems.
