1994/10/26 by R. Peschanski, S. Wallon
Physics and Astronomy · #Black Holes and Theoretical Physics #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #hep-ph
paper · pdf · doi:10.1016/0370-2693(95)00247-i
published as Phys.Lett.B349:357-362,1995 · 10 pages, no figures, plain tex. SPhT-SACLAY preprint T94/090
arxiv created 1994/10/26 · openalex publication_date 1995/04/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider a system of evolution equations for quark and gluon structure functions satisfying the leading-logarithmic behaviour due to both QCD collinear (LLQ2 ) and infrared (LL1/x) singularities. We show that these equations leave undetermined an arbitrary regular function of j in the Mellin-transformed weights. We consider the constraints resulting from energy-momentum conservation and from the decoupling of quark loops in the leading j -plane singularity. These constraints can be fulfilled without influencing the leading-log terms. As a particular consequence of the second constraint, the location of the leading singularity is determined in terms of the (LL1/x) and (LLQ2 ) kernels. It leads to a value significantly lower than the LL1/x evaluation, while remaining at j > 1, and compatible with the behaviour of structure functions observed at HERA.