Electron-Hadron Colliders: EIC, LHeC and FCC-eh

Electron-hadron colliders are the ultimate tool for high-precision quantum chromodynamics studies and provide microscope probing internal structure of hadrons. The electron is an ideal probe proton because it provides unmatched precision electromagnetic interaction, as virtual photon or vector bosons in a clean environment, kinematics which uniquely determined by beam scattered lepton, hadronic final state accounting appropriately radiation. Hadron Electron Ring Accelerator HERA (DESY, Hamburg, Germany) was only electron-hadron collider ever operated (1991–2007) advanced knowledge structure, with implications physics studied RHIC (BNL, Upton, NY) LHC (CERN, Geneva, Switzerland). Recent technological advances field particle accelerators pave way to realize next-generation that deliver higher luminosity enable collisions much broader range energies types than HERA. combine challenges from both hadron machines besides facing their own distinct derived intrinsic asymmetry. This review paper will discuss major features milestones examine designs Electron-Ion Collider (EIC) currently under construction at BNL, CERN’s Large (LHeC), stage design awaiting approval, Future Circular lepton-hadron (FCC-eh).