Enhanced J/Psi-pair production from double parton scatterings in nucleus-nucleus collisions at the Large Hadron Collider

TL;DR

This paper derives a general formula for double-parton scattering cross sections in nucleus-nucleus collisions and applies it to J/psi production at the LHC, revealing significant contributions from double scatterings.

Contribution

It introduces a generic expression for double-parton scattering cross sections in high-energy A-A collisions, linking them to single-parton cross sections and collision centrality.

Findings

Approximately 20-35% of J/psi events involve double scatterings.

Around 240 double-J/psi events are expected per unit midrapidity at 5.5 TeV.

Double J/psi production impacts the interpretation of J/psi suppression.

Abstract

A generic expression of double-parton scattering cross sections in high-energy nucleus-nucleus (A-A) collisions is derived as a function of the corresponding single-parton hard cross sections and of the A-A event centrality. We consider the case of prompt-J/psi production in lead-lead (Pb-Pb) at the CERN Large Hadron Collider and find that about 20% (35%) of the J/psi events in minimum-bias (most central) collisions contain a second J/psi from double parton interactions. In Pb-Pb at 5.5 TeV, in the absence of final-state effects, about 240 double-J/psi events are expected per unit midrapidity and per inverse-nanobarn in the dilepton decay modes. The implications of double-J/psi production on the interpretation of the observed J/psi suppression in A-A collisions are discussed.