English

Parton densities and dipole cross-sections at small x in large nuclei

High Energy Physics - Phenomenology 2009-01-07 v2

Abstract

Unintegrated gluon densities in nuclei, dipole-nucleus cross-sections and quark densities are numerically investigated in the high-colour limit, with the scattering on a heavy nucleus exactly described by the sum of fan diagrams of BFKL pomerons. The initial condition for the evolution in rapidity is quickly forgotten, and the gluon density presents a "supersaturation" pattern, as previous studies indicated. Both dipole-nucleus cross-sections and quark densities present the expected saturation features. Identifying the position in transverse momentum ll of the maximum of the gluon distribution with the saturation momentum Qs(y,b)Q_s(y,b), at large rapidities all distributions depend only on one variable [l/Qs(y,b)][l/Q_s(y,b)] or [rQs(y,b)][rQ_s(y,b)].

Keywords

Cite

@article{arxiv.hep-ph/0104038,
  title  = {Parton densities and dipole cross-sections at small x in large nuclei},
  author = {N. Armesto and M. A. Braun},
  journal= {arXiv preprint arXiv:hep-ph/0104038},
  year   = {2009}
}

Comments

LaTeX, 13 pages, 6 figures in encapsulated postscript included using epsfig; final version, with two added references plus comments, some further clarification, results and conclusions unchanged