Speaker
Description
In pp collisions at LHC energies, charmonium resonances are predominantly produced in hard scattering processes and a subsequent hadronization of the heavy quark pair into a bound state. The production process involves very different energy scales, with the initial quark pair being produced in a high-$Q^2$ process that allows for a perturbative treatment while the following formation of the bound state is a soft process. Moreover, recent observations have shown an enhancement of the $J/\psi$ production in high multiplicity pp collisions compared to minimum bias events at LHC energies. This suggests, that multi parton interactions (MPI) may also play a role in hard processes and not only, as initially thought, in soft particle production. The production of inclusive charmonia as a function of the event activity in pp collisions was studied by ALICE in different transverse momentum intervals at mid- and forward-rapidity. Measurements of the angular correlations between $J/\psi$ mesons and associated hadrons produced in the same event can shed light on the production of $J/\psi$ mesons as well as eventual global event correlations hypothesized to appear in high multiplicity events.
In this talk, we will present recent ALICE results on $J/\psi$ production as a function of event multiplicity in pp collisions at $\sqrt{s}=$13 TeV. These results will be discussed in comparison to measurements at different collision energies and model calculations. Additionally, we will present the current status on $J/\psi$ - hadron angular correlations in pp collisions at $\sqrt{s}=$13 TeV at mid-rapidity.
