Double Prompt J/ψ Hadroproduction in the Parton Reggeization Approach with High-Energy Resummation

We study double prompt J/psi hadroproduction within the nonrelativistic-QCD factorization formalism adopting the parton Reggeization approach to treat initial-state radiation in a gauge invariant and infraredsafe way. We present first predictions for the cross section distributions in the transverse momenta of the subleading J/psi meson and the J/psi pair. Already at leading order in alpha(s), these predictions as well as those for the total cross section and its distributions in the invariant mass m(psi psi) and the rapidity separation vertical bar Y vertical bar of the J/psi pair nicely agree with recent ATLAS and CMS Collaboration measurements, except for the large m(psi psi) and large-vertical bar Y vertical bar regions, where the predictions substantially undershoot the data. In the latter regions, Balitsky-Fadin-Kuraev-Lipatov resummation is shown to enhance the cross sections by up to a factor of 2 and so to improve the description of the data.