Theoretical analysis of double parton scatterings in quarkonium production in proton-proton collisions at the LHC

The production process of quarkonia in proton-proton (pp) collision is a very good probe of the parton structure of the proton. Recent experimental data of the production of J/Ψ+vector boson or quarkonium pairs at the LHC and Tevatron suggest the relevance of double parton scatterings (DPS). We discuss here the single parton scattering (SPS) contribution to the J/Ψ+Z, J/Ψ+W, and J/Ψ+ J/Ψ productions in hadron collisions. By revisiting the computations of the SPS contributions to the J/Ψ+Z and J/Ψ+W productions, we demonstrate that the ATLAS data in fact show evidence for DPS.