Geometric scaling and QCD dynamics in DIS

Summary, in English

DIS data from HERA show a striking regularity as sigma(gamma*p) is a function of the ratio tau = Q(2)/Q(s)(2)(x) only. The scaling function shows a break at 7 t, which has been taken as an indication for saturation. However, besides saturation also the transition between dominance of k(perpendicular to)-ordered (DGLAP) and k(perpendicular to)-non-ordered (BFKL) evolution contributes to a break around this value of 7, as well as the suppression for small Q(2) due to finite quark masses and confinement. In this paper we use a dipole cascade model based on Mueller's dipole model, which also includes energy conservation and pomeron mergings, to investigate the contributions of these different effects to the scaling behaviour. As a result we predict that the scaling function for tau < 1 will be modified when data for Q(2) > 1 GeV2 become available. We also investigate the scaling properties of the charm contribution and the impact parameter dependence of the saturation scale.

• Author: Emil Avsar; Gösta Gustafson
• Department/s: Theoretical Particle Physics - Has been reorganised
• Publishing year: 2007
• Language: English
• Pages: 25-25
• Publication/Series: Journal of High Energy Physics
• Issue: 4
• Links: http://dx.doi.org/10.1088/1126-6708/2007/04/067
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Keywords: PROTON STRUCTURE; HIGH-ENERGY; BFKL POMERON; STATISTICAL PHYSICS; phenomenological models; PICTURE; EVOLUTION; UNITARITY; COHERENCE; SCATTERING; SMALL-X; deep inelastic scattering; QCD
• Status: Published
• ISBN/ISSN/Other: ISSN: 1029-8479