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

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/ψ production in lead–lead (Pb–Pb) at the CERN Large Hadron Collider and find that about 20% (35%) of the J/ψ events in minimum-bias (most central) collisions contain a second J/ψ from double-parton interactions. In Pb–Pb at 5.5 TeV, in the absence of final-state effects, about 240 double-J/ψ events are expected per unit midrapidity and per inverse-nanobarn in the dilepton decay modes. The implications of double-J/ψ production on the interpretation of the observed J/ψ suppression in A–A collisions are discussed.