2002/07/08 by F. Schrempp, A. Utermann
Physics and Astronomy · #hep-ph
published as Acta Phys.Polon. B33 (2002) 3633-3638 · 5 pages, 1 figure, presented at the Xth International Workshop on Deep Inelastic Scattering (DIS 2002), Cracow, 30 April - 4 May 2002, one reference added
arxiv created 2002/07/08 · arxiv updated 2009/11/30
We pursue the intriguing possibility that larger-size instantons build up diffractive scattering, with the marked instanton-size scale <ρ> ≈ 0.5 fm being reflected in the conspicuous ``geometrization'' of soft QCD. As an explicit illustration, the known instanton contribution to DIS is transformed into the intuitive colour dipole picture. With the help of lattice results, the q q-dipole size r is carefully increased towards hadronic dimensions. Unlike pQCD, one now observes a competition between two crucial length scales: the dipole size r and the size ρ of the background instanton that is sharply localized around <ρ> ≈ 0.5 fm. For r exceeding <ρ>, the dipole cross section indeed saturates towards a geometrical limit, proportional to the area π<ρ>2, subtended by the instanton.