Mutual boosting of the saturation scales in colliding nuclei
Abstract
Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. The DGLAP driven gluon distribution turns out to be suppressed at large x, but significantly enhanced at x<<1. This is a high twist effect. In the case of nucleus-nucleus collisions all participating nucleons on both sides get enriched in gluon density at small x, which leads to a further boosting of the saturation scale. We derive reciprocity equations for the saturation scales corresponding to a collision of two nuclei. The solution of these equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q_{sA}^2, in AA compared with pA collisions.
Keywords
Cite
@article{arxiv.1007.1913,
title = {Mutual boosting of the saturation scales in colliding nuclei},
author = {B. Z. Kopeliovich and H. J. Pirner and I. K. Potashnikova and Ivan Schmidt},
journal= {arXiv preprint arXiv:1007.1913},
year = {2011}
}
Comments
12 pages, 4 figures. Extended version to be published in Phys. Lett. B