Exclusive production of quarkonia pairs in collinear factorization framework

In this paper, we analyze the exclusive photoproduction of heavy quarkonia pairs in the collinear factorization framework. We evaluate the amplitude of the process for the 𝐽/𝜓 −𝜂𝑐 quarkonia pair in the leading order of the strong coupling 𝛼𝑠, and express it in terms of generalized parton distributions (GPDs) of gluons in the proton. We make numerical estimates in the kinematics of the Electron Ion Collider and find that, in the photoproduction regime, when the virtuality of the photon is much smaller than the quarkonia mass, the cross section of the process is sufficiently large for experimental studies. We demonstrate that the study of this channel can complement existing studies of gluon GPDs from other channels.