Recent observations of long-range multi-particle azimuthal correlations in p--Pb and high multiplicity pp collisions provided new insights into collision dynamics and opened a possibility to study collective effects in these small systems. New measurement of $p_\mathrm{ T}$-differential elliptic flow ($v_{ 2}$) coefficient for inclusive charged hadrons as well as a variety of identified particle species in p--Pb collisions at $\sqrt{ s_\mathrm{ NN}}=5.02$ TeV recorded by ALICE during the LHC Run 2 data taking are presented. Besides high precision measurements of $v_2(p_\mathrm{ T})$ for $\mathrm{ \pi^\pm, K^\pm}$ and $\mathrm{ p(\bar{ p})}$, the very first results for $\mathrm{ K_{ S}^{ 0}, \Lambda(\bar{ \Lambda})}$ and $\phi$ are shown. In order to eliminate non-flow contamination, a pseudorapidity separation between correlated particles is applied as well as subtraction of remaining non-flow estimate based on a measurement of minimum-bias pp collisions at $\sqrt{ s}=13$ TeV. Moreover, reported characteristic mass ordering and approximate NCQ and $\mathrm{ KE_T}$ scaling of $v_{ 2}$ allows to test various theoretical models, constrain the initial conditions, and probe the origin of collective behavior in small collision systems.
Categories: nucl-ex