Geometric scaling above the saturation scale
Description
We show that the evolution equations in QCD predict geometric scaling for quark and gluon distribution functions in a large kinematical window, which extends above the saturation scale up to momenta Q2 of order 100 GeV2. For Q2<Q2s, with Qs the saturation momentum, this is the scaling predicted by the Colour Glass Condensate and by phenomenological saturation models. For 1≤ ln(Q2/Qs2)<<ln(Qs2/Λ2QCD), we show that the solution to the BFKL equation shows approximate scaling, with the scale set by Qs. At larger Q2, this solution does not scale any longer. We argue that for the intermediate values of Q2 where we find scaling, the BFKL rather than the double logarithmic approximation to the DGLAP equation properly describes the dynamics. We consider both fixed and running couplings, with the scale for running set by the saturation momentum. The anomalous dimension which characterizes the approach of the gluon distribution function towards saturation is found to be close to, but lower than, one half
Additional details
Identifiers
- PII
- S0375947402010102;
Publishing Information
- Journal Title
- Nuclear Physics. A
- Journal Volume
- 708
- Journal Issue
- 3-4
- Journal Page Range
- p. 327-352
- ISSN
- 0375-9474
- CODEN
- NUPABL
INIS
- Country of Publication
- Netherlands
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 34006352
- Subject category
- S72: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS;
- Descriptors DEI
- COLOR MODEL; CROSS SECTIONS; DISTRIBUTION FUNCTIONS; GLUONS; PARTICLE KINEMATICS; QUANTUM CHROMODYNAMICS; QUARKS; S MATRIX; SCALING LAWS
- Descriptors DEC
- BOSONS; COMPOSITE MODELS; ELEMENTARY PARTICLES; FERMIONS; FIELD THEORIES; FUNCTIONS; MATHEMATICAL MODELS; MATRICES; PARTICLE MODELS; POSTULATED PARTICLES; QUANTUM FIELD THEORY; QUARK MODEL
Optional Information
- Copyright
- Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.