Review on recent results of J/$ψ$ production at STAR
Abstract
Studying the production of J/$\psi$ (bound state of charm and anti-charm quark) in proton-proton collisions gives an opportunity to test quantum chromodynamics (QCD) calculations, as the production of J/$\psi$ involves both perturbative and non-perturbative processes. However, theoretical calculations are still unable to fully and simultaneously explain experimental results, such as polarization and $p_\text{T}$ spectra measured in different kinematic regimes and colliding energies. More studies are needed to investigate J/$\psi$ production mechanism. In heavy-ion collisions, charmonia can be used to study the properties of the medium as they are expected to dissociate in the medium when the Debye radius, inversely proportional to the medium temperature, becomes smaller than their size. Other competing effects, such as recombination, have also been found to modify the observed J/$\psi$ yield in heavy-ion collisions. We review recent measurements of the J/$\psi$ production in proton-proton and heavy-ion collisions at various collision energies measured with the STAR experiment at RHIC. The data are compared with recent model calculations on charmonia production.