Multiparticle correlations and higher order harmonics in pPb collisions at s_NN=8.16TeV

The elliptic and higher-order azimuthal anisotropy Fourier harmonics (v_n) are obtained for pPb collisions at s_NN=8.16TeV over a wide range of event multiplicities based on multiparticle correlations. The data were collected by the CMS experiment during the 2016 LHC run. A sample of peripheral PbPb collisions at s_NN=5.02TeV covering a similar range of event multiplicities to the pPb results is also analyzed for comparison. The ratios of different harmonic moments are obtained for both v₂ and v₃ with high precision, which allows a direct comparison to theoretical predictions assuming a hydrodynamic evolution of the created medium with initial-state density fluctuations, particularly probing the non-Gaussian nature of initial-state fluctuations in small collision systems. The presented results provide crucial insights into the origin of collective long-range correlations observed in small collision systems.