Investigation of possible hadronic flow in √{sNN}=5.02 TeV p -Pb collisions

Using the ultrarelativistic quantum molecular dynamics (UrQMD) model, we investigate azimuthal correlations in p -Pb collisions at √{s_NN}=5.02 TeV . Comparison with the experimental data shows that UrQMD cannot reproduce the multiplicity dependence of two- and four-particle cumulants, especially the transition from positive to negative values of c₂{4 } in high-multiplicity events, which has been taken as experimental evidence of collectivity in p -Pb collisions. Meanwhile, UrQMD cannot describe the differential elliptic flow v₂(p_T) of all charged hadrons at various multiplicity classes. These discrepancies show that the simulated hadronic p -Pb systems cannot generate enough collective flow as observed in experiment, the associated hadron emissions are largely influenced by nonflow effects. However, the characteristic v₂(p_T) mass ordering of pions, kaons, and protons is observed in UrQMD, which is the consequence of hadronic interactions and not necessarily associated with strong fluid-like expansions.