Multiparticle correlations and higher order harmonics in pPb collisions at $\sqrt{s_{_\text{NN}}} = 8.16~\mathrm{TeV}$

The second- and third-order azimuthal anisotropy Fourier harmonics are studied in pPb collisions at $\sqrt{s_{_\text{NN}}}=8.16~\mathrm{TeV}$ over a wide range of event multiplicities. The second-order, ``elliptic'' harmonic moment is obtained through four-, six-, and eight-particle correlations and the third-order, ``triangular'' harmonic moment is studied using four-particle correlations. The data were collected by the CMS experiment during the 2016 LHC run. A sample of peripheral PbPb collisions at $\sqrt{s_{_{\text{NN}}}}=5.02~\mathrm{TeV}$, covering a similar range of event multiplicities to the pPb results, is also analyzed. Theoretical predictions that assume a hydrodynamic evolution of the created medium with initial-state density fluctuations are compared to the experimental results.