Higher-twist operator effects to parton densities at small x

We investigate the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product expansion are taken into account. The results are in very good agreement with deep inelastic scattering experimental data from HERA.Comment: 4 pages, latex. Talk presented at the DIS2001 Workshop, Bologna, April 200

About QCD coupling constant at NNLO from DIS data

We give a brief review of our recent QCD analysis carried out over the deep inelastic scattering data on F2 structure function and in the non-singlet approximation to the accuracy up to next-to-next-to-leading-order. Specifically, analysis was performed over high statistics deep inelastic scattering data provided by BCDMS, SLAC, NMC and BFP collaborations. For the coupling constant the following value alpha_s(M_Z^2) = 0.1167 \pm 0.0022 was found.Comment: 11 pp, 2 figs, contribution to the Proceedings of XLIV PNPI Winter School held in Roschino (Russia) on 9-14 March, 201