Flow of strange and charged particles in pPb and PbPb collisions at LHC energies

Abstract

Observation of a long-range near-side two-particle correlation (known as the“Ridge”) in high-multiplicity pPb and pp collisions opened up new opportunities of exploring novel QCD dynamics in small collision systems. Latest CMS results in pPb and PbPb collisions will be shown: (1) The multi-particle correlation in pPb collisions will be presented for the high multiplicity events, indicating the collective behavior in small collision systems. (2) Identified pT spectra of π+/π-, K+/K-, and p/p¯ in pPb collisions show a strong multiplicity dependence, which indicates radial flow at high multiplicity events. (3) The second-order anisotropy harmonics (v2) of strange particle K0s and Λ/Λ¯ are extracted from long-range correlations as a function of particle multiplicity and pT. The mass ordering effect of vn at low pT as predicted by hydrodynamics also points to the strong collective nature of expanding medium in small collision systems. Finally, the possible constituent quark number of scaling of v2 between mesons and baryons may indicate the deconfinement in small systems.