High-energy factorization and small-x deep inelastic scattering beyond leading order

Abstract

High-energy factorization in QCD is investigated beyond leading order and its\nrelationship to the factorization theorem of mass singularities is established\nto any collinear accuracy. Flavour non-singlet observables are shown to be\nregular at small x order by order in perturbation theory. In the singlet\nsector, we derive the relevant master equations for the space-like evolution of\ngluons and quarks. Their solution enables us to sum next-to-leading corrections\nto the small-x behaviour of quark anomalous dimensions and deep inelastic\nscattering coefficient functions. We present results in both MSbar and DIS\nfactorization schemes.\n