CMS results on collectivity in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 and 5.02~TeV

Nonlinear response coefficients of higher-order $v_{n}$ anisotropy harmonics for charged particles, as a function of transverse momentum ($p_{\mathrm{T}}$) and collision centrality, are measured in PbPb collisions at $\sqrt{s_{NN}}$ = 2.76 and 5.02~TeV. The nonlinear response coefficients are obtained using $v_{n}$ harmonics measured with respect to their own plane and the mixed harmonics. Using a fine splitting between $v_{2}\{4\}$ and $v_{2}\{6\}$ cumulants, the centrality dependence of the elliptic flow skewness is measured at 5.02 TeV PbPb collisions. The CMS also measured the $v_{2}$ and $v_{3}$ anisotropy harmonics of charged particles and prompt $D^{0}$ mesons at $\lvert y\rvert \le$ 1 as a function of $p_{\mathrm{T}}$ and centrality in PbPb data at $\sqrt{s_{NN}}$ = 5.02~TeV collected with the CMS detector. Prompt $D^{0}$ mesons, formed from the $c$ quarks produced via initial hard scatterings, are separated up to a high extent from nonprompt $D^{0}$ mesons emerged from decays of b hadrons. The results indicate that the charm quarks interact strongly with the QGP medium. Comparisons between theoretical models and data provide new constraints on the initial-state conditions and the interaction between charm quarks and the QGP medium.