Sullivan process near threshold and the pion gravitational form factors

We propose a novel method to experimentally access the gravitational form factors (GFFs) of the charged pion ${\pi }^{+}$ through the Sullivan process in electron-proton scattering. We demonstrate that the cross sections of $J\mathrm{/}\psi$-photoproduction and $\phi$-electroproduction near the respective thresholds are dominated by the gluon GFF of the pion to next-to-leading order in perturbative QCD. We predict cross sections for the Electron-Ion Collider and the Jefferson Lab experiments.