Published October 7, 2002 | Version v1
Journal article

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

Optional Information

Copyright
Copyright (c) 2002 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.