Evidence of sub-nucleonic degrees of freedom in J/$\psi$ photoproduction in ultraperipheral collisions at the CERN Large Hadron Collider

TL;DR

This paper investigates J/ψ photoproduction in ultra-peripheral heavy ion collisions at LHC energies, providing insights into sub-nucleonic structures through Monte Carlo simulations and comparison with experimental data.

Contribution

The study introduces an extended Monte Carlo model for incoherent J/ψ photoproduction in UPCs, incorporating re-scattering effects and comparing results across different collider energies.

Findings

Re-scattering significantly affects J/ψ survival in PbPb collisions.

Model results align with experimental data from RHIC and LHC.

Evidence suggests sub-nucleonic degrees of freedom influence photoproduction processes.

Abstract

We present calculations for the incoherent photoproduction of J/$\psi$ vector mesons in ultra-peripheral heavy ion collisions (UPC) in terms of hadronic interactions. This study was carried out using the recently developed Monte Carlo model CRISP extended to include UPCs at LHC energies. A careful study of re-scattering and destruction of the J/$\psi$ particles is presented for PbPb collisions at $\sqrt{s_{NN}} = 2.76$ TeV. We have also compared our method to AuAu collisions at $\sqrt{s_{NN}} = 200$ GeV measured at RHIC.