Gluon distributions from Oliveira-Martin-Ryskin combined BFKL+DGLAP evolution equations

Abstract

Kwiecinski, Martin, Stasto [13] argue for inclusion of DGLAP terms into BFKL evolution of unintegrated gluon density. The equation was reformulated by Oliveira, Martin, Ryskin [6] employing the opening angle {\theta} = k/xp as the evolution variable. It leads to a description of a {\theta}-integrated gluon density. This paper is a numerical study of these two similar combined BFKL+DGLAP formulations. It is a demonstration of feasibility of the new approach. The different ways of subtracting the contribution common for BFKL and DGLAP proposed in [13] and [6] are compared. The numerical tests confirm that the {\theta} variable is a more natural evolution variable for this kind of equation.

Comments: 10 pages, 2 figures