“…However, when the parton density becomes large, annihilation processes become active and they suppress the gluon radiation and, so, they tame the rapid increase of the parton densities at a new saturation scale Q s (x) [2,6,7]. The theoretical approach as well as understanding the physics of parton saturation is one of the most challenging problem of QCD which has stimulated the development of new methods [2,6,7,8,9,10,11,12], surprisingly, all approaches lead to the same nonlinear evolution equation.…”