The primary goal of the ultrarelativistic heavy-ion collision programme at the LHC is to study the properties of the quark-gluon plasma (QGP), a state of strongly interacting matter that exists at high temperatures and energy densities. Anisotropic flow, studied using the anisotropy of the momentum distribution of final state particles, is sensitive to the fluctuating initial geometry of the overlap region of the colliding nuclei, as well as to the properties of the QGP. Recent developments show that higher-order anisotropic flow contains two components, the linear mode corresponds to the same order initial anisotropy coefficient while the non-linear flow mode is originated from lower- order initial anisotropy. The study of linear and non-linear flow modes have the potential to improve the accuracy of the extracted transport coefficients of QGP. In this seminar, the latest ALICE measurements of anisotropic flow and its non-linear modes with both inclusive and identified hadrons in Pb–Pb collisions at $\sqrt{s_{NN}}=2.76$ and 5.02 TeV will be presented. The comparisons of precision measurements and state-of-the-art hydrodynamic calculations offer new insights into the geometry of the fluctuating initial state, and further probe the dynamical evolution of the QGP.
Michelangelo Mangano, Monica Pepe-Altarelli and Guillaume Unal