The evolution of unpolarized singlet structure functions at small x

A systematic study is performed of the impact of the various resummed small-x contributions to the anomalous dimensions and coefficient functions on the evolution of unpolarized structure functions in deep-inelastic scattering. The proton structure functions F-2(p) and F-L(p) as well as the photon structure function F-2(gamma) are considered together with the corresponding parton densities. The general analytic solution of the evolution equations in Mellin-N space is derived, and different approximate solutions are compared. Potential effects of less singular small-x terms in the anomalous dimension and coefficient functions are discussed. [S0556-2821(98)02413-8].