Threshold Upsilon-meson photoproduction at the EIC and EicC

High-accuracy (sic)-meson photoproduction data from EIC and EicC experiments will allow the measurement of the near-threshold total cross section of the reaction gamma p -> (sic)p, from which the absolute value of the (sic)p-scattering length, vertical bar alpha((sic)p)vertical bar, can be extracted using a vector-meson dominance model. For this evaluation, we used (sic)-meson photoproduction quasidata from the QCD approach (the production amplitude can be factorized in terms of gluonic generalized parton distributions and the quarkonium distribution amplitude). A comparative analysis of vertical bar alpha((sic)p)vertical bar with the recently determined scattering lengths for omega p, phi p, and J/psi p using the A2, CLAS, and GlueX experimental data are performed. The role of the "young" vector-meson effect is evaluated.