Observables in exclusive heavy quarkonium electroproduction at NLO and prospects for the EIC

Abstract: We perform various phenomenological studies of exclusive heavy-quarkonium electroproduction in $ep$ collisions that are relevant for both the existing measurements from HERA and the forthcoming Electron-Ion Collider (EIC). We provide quantitative predictions at next-to-leading order (NLO) in perturbative QCD (pQCD) for various observables accessible at HERA for $J/ψ$ electroproduction that serve as valuable benchmarks across a broad range of photon virtualities $Q<sup>2$ and $γ^* p$ centre-of-mass energies. We then discuss how the forthcoming EIC will complement existing measurements and end by advocating the need for a dedicated and systematic resummation framework for $J/ψ$ electroproduction at large $Q<sup>2$.