arXiv:hep-ph/0402173·v2·High Energy Physics — Phenomenology
Small x behavior of parton distributions. A study of higher twist effects
Alexei Yu. Illarionov (1 and 2)🇮🇹 · Anatoly V. Kotikov (2 and 3)🇩🇪 · Gonzalo Parente (4) ((1) Dipartimento di Fisica ``Enrico Fermi'', Universita di Pisa, and INFN, Sezione di Pisa, Italy, (2) Joint Institute for Nuclear Research, Dubna, Moscow region, Russia, (3) Institut fuer Theoretische Teilchenphysik, Universitat Karlsruhe, Germany, (4) Departamento de Fisica de Particulas, Universidade de Santiago de Compostela, Spain)🇪🇸
Abstract
Higher twist corrections to the structure function F_2 at small x are studied for the case of a flat initial condition for the twist-two QCD evolution in the next-to-leading order approximation. We present an analytical parameterization of the contributions from the twist-two and higher twist operators of the Wilson operator product expansion. Higher twist terms are evaluated using two different approaches, one motivated by BFKL and the other motivated by the renormalon formalism. The results of the latter approach are in very good agreement with deep inelastic scattering data from HERA.
Comments: 46 pages, 9 figures, typeset using REVTeX. Misprints corrected, new results, discussions, references and acknowledgements added, 2 pictures replaced. The conclusions remain unchanged