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Energy conservation and saturation in small-x evolution

Avsar, Emil LU ; Gustafson, Gösta LU and Lönnblad, Leif LU (2005) In Journal of High Energy Physics
Abstract
Important corrections to BFKL evolution are obtained from non-leading contributions and from non-linear effects due to unitarisation or saturation. It has been diffcult to estimate the relative importance of these effects, as NLO effects are most easily accounted for in momentum space while unitarisation and saturation are easier in transverse coordinate space. An essential component of the NLO contributions is due to energy conservation effects, and in this paper we present a model for implementing such effects together with saturation in Mueller's dipole evolution formalism. We find that energy conservation severely dampens the small-x rise of the gluon density and, as a consequence, the onset of saturation is delayed. Using a simple... (More)
Important corrections to BFKL evolution are obtained from non-leading contributions and from non-linear effects due to unitarisation or saturation. It has been diffcult to estimate the relative importance of these effects, as NLO effects are most easily accounted for in momentum space while unitarisation and saturation are easier in transverse coordinate space. An essential component of the NLO contributions is due to energy conservation effects, and in this paper we present a model for implementing such effects together with saturation in Mueller's dipole evolution formalism. We find that energy conservation severely dampens the small-x rise of the gluon density and, as a consequence, the onset of saturation is delayed. Using a simple model for the proton we obtain a reasonable qualitative description of the x-dependence of F-2 at low Q(2) as measured at HERA even without saturation effects. We also give qualitative descriptions of the energy dependence of the cross section for gamma*gamma* and gamma*-nucleus scattering. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
phenomenological models, jets, QCD, parton model
in
Journal of High Energy Physics
issue
7
publisher
Springer
external identifiers
  • wos:000230854400016
  • scopus:23844550246
ISSN
1126-6708
DOI
10.1088/1126-6708/2005/07/062
language
English
LU publication?
yes
id
6779dc05-d645-4291-b4dc-99e82b815b16 (old id 231502)
date added to LUP
2007-08-10 10:37:08
date last changed
2017-08-27 04:02:41
@article{6779dc05-d645-4291-b4dc-99e82b815b16,
  abstract     = {Important corrections to BFKL evolution are obtained from non-leading contributions and from non-linear effects due to unitarisation or saturation. It has been diffcult to estimate the relative importance of these effects, as NLO effects are most easily accounted for in momentum space while unitarisation and saturation are easier in transverse coordinate space. An essential component of the NLO contributions is due to energy conservation effects, and in this paper we present a model for implementing such effects together with saturation in Mueller's dipole evolution formalism. We find that energy conservation severely dampens the small-x rise of the gluon density and, as a consequence, the onset of saturation is delayed. Using a simple model for the proton we obtain a reasonable qualitative description of the x-dependence of F-2 at low Q(2) as measured at HERA even without saturation effects. We also give qualitative descriptions of the energy dependence of the cross section for gamma*gamma* and gamma*-nucleus scattering.},
  author       = {Avsar, Emil and Gustafson, Gösta and Lönnblad, Leif},
  issn         = {1126-6708},
  keyword      = {phenomenological models,jets,QCD,parton model},
  language     = {eng},
  number       = {7},
  publisher    = {Springer},
  series       = {Journal of High Energy Physics},
  title        = {Energy conservation and saturation in small-x evolution},
  url          = {http://dx.doi.org/10.1088/1126-6708/2005/07/062},
  year         = {2005},
}