Production of high-invariant-mass charmonium pairs in proton-proton interaction.

Interpretations of the most recent experimental data on double J/ ψ production are discussed. It is shown that a significant signal in the region of high invariant masses of a J/ ψ pair may be a piece of evidence not only in favor of the dominance of double parton scattering in this region. The diagrams involving two-gluon exchange in the t channel, which are considered in the present study, make a commensurate contribution to the above production process in the region in question and also to the double production of J/ ψ mesons characterized by a large rapidity difference. [ABSTRACT FROM AUTHOR]