Particle correlations and their implication to collectivity in pPb and PbPb from CMS

The long-range two-particle correlation functions reveal the near-side ridge structures in high-multiplicity pp, pPb and PbPb collisions at the Large Hadron Collider (LHC). The model that takes into account the collective flow originated from the initial-state geometry fluctuation can successfully describe the measured long-range correlation functions of charged particles. In this review paper, the recent experimental data on the long-range correlations and the extracted elliptic and triangular flow parameters in pPb and PbPb collisions from the Compact Muon Solenoid (CMS) experiment are summarized. The flow parameters from the long-range correlation analyses are compared with those from the multiparticle cumulants and the Lee-Yang Zeros (LYZ) method. In addition, the pseudorapidity dependence of long-range two-particle correlation functions in pPb and the deduced flow parameters for identified strange hadrons ($K_{S}^{0}$ and $\Lambda/\bar{\Lambda}$) in pPb and PbPb are also presented to provide more insights on the long-range correlations and flow dynamics.