Anisotropy in pPb and PbPb collisions from CMS

The recent CMS results on anisotropic particle emission will be presented. Consistency between the results obtained using four-, six and eigth-particle correlation as well as the Lee-Yang zero method reveals a multi-particle nature of the long-range correlations observed in pPb collisions. By correlating an identified strange hadron ($K^{0}_{S}$ or $\Lambda$/$\bar{\Lambda}$) with a charged particle, at large relative pseudorapidity, the magnitude of the elliptic and triangular flow of strange particles from both pPb and PbPb collisions have been extracted. The results for $K^{0}_{S}$ and $\Lambda$/$\bar{\Lambda}$ scaled by the number of constituent quarks as a function of transverse kinetic energy per quark are in a mutual agreement (within 10\pct) for both $v_{2}$ and $v_{3}$ over a wide range of particle transverse kinetic energy and event multiplicities. Due to the initial-state fluctuations, the event-plane angle depends on both, transverse momenta ($p_{T}$) and pseudorapidity ($\eta$), which consequently induce breaking of the factorization of the two-particle azimuthal anisotropy into a product of single-particle anisotropies. For $p_{T}$, maximal effect of factorization breaking of about 20\pct is observed in ultra-central PbPb collisions. For $\eta$, the effect is weakest for mid-central PbPb events and gets larger for more central or peripheral PbPb collisions as well as for high multiplicity pPb collisions. The experimental results are consistent with recent hydrodynamic predictions in which the factorization breakdown effect is incorporated. It is found that the effect is mainly sensitive to the initial-state conditions rather than the shear viscosity of the medium.