Institution: | aDipartimento di Fisica “E.Amaldi”, Università Roma Tre, INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Roma, Italy bCERN, Department of Physics, Theory Division, CH-1211 Genève 23, Switzerland cSchool of Physics, University of Edinburgh, Edinburgh EH9 3JZ, Scotland, UK dDipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, Via Celoria 16, I-20133 Milan, Italy |
Abstract: | We extend our previous results on small-x resummation in the pure Yang–Mills theory to full QCD with nf quark flavours, with a resummed two-by-two matrix of resummed quark and gluon splitting functions. We also construct the corresponding deep-inelastic coefficient functions, and show how these can be combined with parton densities to give fully resummed deep-inelastic structure functions F2 and FL at the next-to-leading logarithmic level. We discuss how this resummation can be performed in different factorization schemes, including the commonly used scheme. We study the importance of the resummation effects by comparison with fixed-order perturbative results, and we discuss the corresponding renormalization and factorization scale variation uncertainties. We find that for x below 10?2 the resummation effects are comparable in size to the fixed order NNLO corrections, but differ in shape. We finally discuss the phenomenological impact of the small-x resummation, specifically in the extraction of parton distribution from present day experiments and their extrapolation to the kinematics relevant for future colliders such as the LHC. |