Orateur
Description
In this study, we investigate the polarization parameters of J/$\psi$ and $\psi$(2S) in proton-proton (pp) collisions at LHC energies, utilizing PYTHIA8 to analyze dimuon angular distributions. Our findings reveal intriguing insights: at low transverse momentum ($p_{T}$), both particles exhibit longitudinal polarization, transitioning to transverse polarization at higher $p_{T}$ in both helicity and Collins-Soper reference frames. Moreover, longitudinal polarization is evident across all energies, while transverse polarization is prominent in the Collins-Soper frame. Notably, the degree of longitudinal polarization of $\psi$(2S) increases with charged particle multiplicity, contrasting the relatively constant polarization observed for J/$\psi$. Although we find no clear dependence of polarization parameters on rapidity, future studies with wider kinematics acceptance, such as the ALICE 3 setup, could shed light on this aspect. Our results, based on pQCD-based PYTHIA8 simulation, suggest the necessity for comprehensive studies utilizing theoretical models in conjunction with experimental data to fully understand charmonia polarization in ultra-relativistic pp collisions.
