On the understanding and use of "unintegrated" parton distributions in small-x QCD

Abstract

We review and discuss the use of TMD, or "unintegrated", gluon distributions in the domain of small-x physics. The definitions employed, and the hazards of the naive applications of the TMD factorization and the associated gluon distributions are discussed.

Comments: 10 pages, based on talk give at the workshop "QCD evolution of parton distributions: from collinear to non-collinear case", 8 - 9 Apr 2011