title: Locality of quark-hadron duality and deviations from quark counting rules above the resonance region.
abstract: We show how deviations from the dimensional scaling laws for exclusive processes may be related to a breakdown in the locality of quark-hadron duality. The essential principles are illustrated in a pedagogic model of a composite system with two spinless charged constituents, for which a dual picture for the low-energy resonance phenomena and high-energy scaling behavior can be established. We introduce the concept of "restricted locality" of quark-hadron duality and show how this results in deviations from the perturbative quantum chromodynamics quark counting rules above the resonance region. In particular, it can be a possible source for oscillations about the smooth quark counting rule, as seen, e.g., in the 90-degree differential cross sections for gammap-->pi(+)n.
authors.affiliation: Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom. Qiang.Zhao@surrey.ac.uk
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Frank E
authors.initials: FE
authors.lastname: Close