Effective Field Theory for Diffraction

A significant fraction of scattering events at colliders are diffractive, with large angular gaps devoid of particles. Unlike the primary hard scattering processes studied at hadron colliders, so far a first principle theoretical description of these diffractive events has been lacking. These diffractive processes are believed to be important for unlocking the small-x regime where protons and ions become saturated with gluons, and hence are a key target for both the LHC and a future Electron-Ion Collider. In this talk I discuss new tools for describing diffractive scattering that are based on effective field theory, and present the first factorization formula for the forward (Regge) physics in e-p diffractive scattering. This rigorous result yields a way of assessing earlier models used in diffractive fits, provides power counting tools that predict larger than expected asymmetry structure functions, and enables the size of color singlet exchange (Pomeron) contributions to be assessed relative to a newly identified background caused by color non-singlet exchanges.