$J/\psi$ and $\psi$(2S) polarization in proton-proton collisions at energies available at the CERN Large Hadron Collider using PYTHIA8

TL;DR

This study uses PYTHIA8 simulations to analyze the polarization of $J/$ and $$(2S) charmonium states in proton-proton collisions at LHC energies, providing insights into their production mechanisms.

Contribution

It offers the first detailed simulation-based analysis of charmonium polarization across multiple LHC energies, considering various kinematic variables and decay channels.

Findings

Qualitative agreement with experimental polarization data.

Polarization parameters vary with transverse momentum, rapidity, and multiplicity.

Provides a comprehensive framework for future polarization studies.

Abstract

The production mechanisms of charmonium states in both hadronic and heavy-ion collisions hold great significance for investigating the hot and dense QCD matter. Studying charmonium polarization in ultra-relativistic collisions can also provide insights into the underlying production mechanisms. With this motivation, we explore the $J/\psi$ and $\psi$(2S) polarization in proton+proton collisions at $\sqrt{s}$ = 7, 8, and 13 TeV using a pQCD-inspired Monte-Carlo event generator called PYTHIA8. This work considers reconstructed quarkonia through their dimuons decay channel in the ALICE forward rapidity acceptance range of $2.5 < y_{\mu \mu} < 4$. Further, we calculate the polarization parameters $\lambda_{\theta}$, $\lambda_{\phi}$, $\lambda_{\theta \phi}$ from the polar and azimuthal angular distributions of the dimuons in helicity and Collins-Soper frames. This study presents a comprehensive measurement of the polarization parameters as a function of transverse momentum, charged-particle multiplicity, and rapidity at the LHC energies. Our findings of charmonium polarization are in qualitative agreement with the corresponding experimental data.