Quarkonium production and elliptic flow in small systems measured with ALICE

Abstract

Abstract. Quarkonium production in hadronic collisions provides a unique testing ground for understanding quantum chromodynamics (QCD) since it involves both perturbative and non-perturbative regimes of this theory. A variety of experimental observables, such as the production cross-section, polarization, particle correlations, serve as insights into the phenomenology of the quarkonium production and help constrain the theoretical models. Measurements of quarkonia as a function of multiplicity probe multiple parton interactions (MPI), i.e., several parton-parton interactions occurring in a single hadron-hadron collision. Finally, measurements of the azimuthal correlation structure of emitted particles in high multiplicity pp collisions can probe the existence of collective behaviour in small systems. The ALICE detector can reconstruct inclusive quarkonia over a broad kinematical range, spanning from mid-rapidity up to forward rapidity, and down to zero transverse momentum. In addition, at midrapidity, the non-prompt charmonium contribution can be separated from the prompt contribution. In these proceedings, we present new results on the inclusive, prompt and non-prompt J/ψ production cross sections measured by ALICE in pp collisions at different collision energies. The self-normalized ψ(2S)-to-J/ψ yield ratio measurement is investigated as a function of the charged particle multiplicity in pp collisions at √S = 13. TeV. Finally, the first measurement of the J/ψ elliptic flow (v2) in high multiplicity pp collisions at √S = 13. TeV is presented. Results will be compared to theoretical models.