Elliptic flow of identified hadrons in small collisional systems measured with ALICE

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 measurements of p 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 sNN=5.02TeV are presented. The data was collected by ALICE during the LHC Run 2 data taking. Besides high precision measurements of v2(pT) for π± , K± and p( p‾ ), the first results for KS0 , Λ(Λ‾) and ϕ 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 s=13TeV . Moreover, the reported characteristic mass ordering and approximate number of constituent quarks (NCQ) and transverse kinetic energy (KE T ) scaling of v 2 allow to test various theoretical models, constrain the initial conditions, and probe the origin of collective behavior in small collision systems.