Quarkonia production as a function of charged-particle multiplicity in pp collisions at $\sqrt{s}=13$ TeV with ALICE

Abstract

In pp collisions at LHC energies, heavy quarks are produced in initial hard scatterings and then these quarks hadronize in either open heavy-flavor hadrons or quarkonia (e.g. J/$\psi$, $\psi (2S)$, ${\rm Y}$). The study of quarkonium production as a function of charged-particle multiplicity links soft and hard processes and allows one to study their interplay. While a linear increase of quarkonium production as a function of charged-particle multiplicity can be reasonably well understood in the context of multi-parton interactions, the observation of deviations with respect to a linear increase requires a more detailed description of the collision. In this contribution, we will present the latest ALICE measurements at forward rapidity for J/$\psi$ and ${\rm Y}$ production as a function of charged-particle multiplicity in pp collisions at $\sqrt{s}=13$ TeV. The first measurement of the double ratios of relative yield of ${\rm Y}(2S)$ over ${\rm Y}(1S)$ and J/$\psi$ over ${\rm Y}(1S)$ as a function of charged-particle multiplicity will also be shown.

4 pages, 4 figures, Proceedings of The Eighth Annual Conference on Large Hadron Collider Physics(LHCP 2020), 25-30 May, 2020